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  Subjects -> CHEMISTRY (Total: 909 journals)
    - ANALYTICAL CHEMISTRY (56 journals)
    - CHEMISTRY (643 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (43 journals)
    - ORGANIC CHEMISTRY (47 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (643 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 14)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 31)
ACS Catalysis     Hybrid Journal   (Followers: 53)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 23)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 28)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 44)
ACS Nano     Hybrid Journal   (Followers: 329)
ACS Photonics     Hybrid Journal   (Followers: 15)
ACS Symposium Series     Full-text available via subscription  
ACS Synthetic Biology     Hybrid Journal   (Followers: 25)
Acta Chemica Iasi     Open Access   (Followers: 6)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 62)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 77)
Advances in Chemical Science     Open Access   (Followers: 21)
Advances in Chemistry     Open Access   (Followers: 27)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 20)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Environmental Chemistry     Open Access   (Followers: 7)
Advances in Enzyme Research     Open Access   (Followers: 11)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 27)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Polymer Science     Hybrid Journal   (Followers: 45)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 4)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 8)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 70)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 22)
American Journal of Chemistry     Open Access   (Followers: 34)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 15)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Analyst     Full-text available via subscription   (Followers: 37)
Angewandte Chemie     Hybrid Journal   (Followers: 186)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 276)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 15)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 26)
Applied Surface Science     Hybrid Journal   (Followers: 34)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 3)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 4)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 384)
Biochemistry Insights     Open Access   (Followers: 7)
Biochemistry Research International     Open Access   (Followers: 7)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 24)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 142)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 93)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 20)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 25)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 12)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
Carbohydrate Research     Hybrid Journal   (Followers: 25)
Carbon     Hybrid Journal   (Followers: 70)
Catalysis for Sustainable Energy     Open Access   (Followers: 10)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 10)
Catalysis Science and Technology     Hybrid Journal   (Followers: 10)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 14)
Cellulose     Hybrid Journal   (Followers: 13)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 2)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 23)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 75)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 28)
Chemical Physics Letters : X     Open Access  
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 220)
Chemical Science     Open Access   (Followers: 29)
Chemical Technology     Open Access   (Followers: 36)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 21)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 33)
Chemistry & Industry     Full-text available via subscription   (Followers: 9)
Chemistry - A European Journal     Hybrid Journal   (Followers: 186)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 21)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 46)
Chemistry of Materials     Hybrid Journal   (Followers: 283)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Full-text available via subscription   (Followers: 21)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 11)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 5)
Cogent Chemistry     Open Access   (Followers: 2)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 11)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 23)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 8)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 4)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 7)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 8)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 6)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 9)
Current Science     Open Access   (Followers: 77)
Current Topics in Medicinal Chemistry     Hybrid Journal   (Followers: 9)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 2)
Dalton Transactions     Full-text available via subscription   (Followers: 26)

        1 2 3 4 | Last

Similar Journals
Journal Cover
Carbon
Journal Prestige (SJR): 2.226
Citation Impact (citeScore): 7
Number of Followers: 70  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0008-6223
Published by Elsevier Homepage  [3160 journals]
  • Ultrahigh stretching bond force constants of linear chains of carbon and
           boron nitride
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): C. Cab, J. Medina, M.L. Casais-Molina, G. Canto, A. Tapia Stretching bond force constants (kr) describing the bond stiffness of linear chains of carbon (LCC), boron (LBC), and boron nitride (LBNC) are calculated using density functional theory. The effect of employing different exchange-correlation functionals for kr calculation is discussed using the local density approximation (LDA), the generalized gradient approximation (GGA) and two nonlocal hybrid density functionals (PBE0 and HSE06). The highest value of kr was obtained for LCC using LDA (12.25 mdyn/Å), while the lowest value was for LBC using GGA (4.82 mdyn/Å). For the first time for LBNC, the kr values of 10.56, 10.35, 10.99 and 11.00 mdyn/Å were predicted using LDA, GGA, PBE0 and HSE06 respectively. The comparison between these three linear chains allowed for the elucidation of the effect and differences in bond stiffness of carbon substitution by boron and boron nitride atoms inside an atomic linear arrangement. Our theoretical calculations suggest that under tension, linear boron nitride chains are the second stiffest nanomaterials ever reported up to now.Graphical abstractImage 1
       
  • Growth of umbrella-like millimeter-scale single-crystalline graphene on
           liquid copper
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Chitengfei Zhang, Rong Tu, Mingdong Dong, Jun Li, Meijun Yang, Qizhong Li, Ji Shi, Haiwen Li, Hitoshi Ohmori, Song Zhang, Lianmeng Zhang, Takashi Goto Novel single-crystalline umbrella-like graphene (ULG) domains with the diameter up to 0.6 mm were achieved on liquid copper by atmospheric pressure chemical vapor deposition (APCVD). ULG exhibits 6-fold symmetry with 6 ribs. Raman spectroscopy analysis revealed that the ULG was few-layer graphene with ultralow level of defects. Scanning Tunneling Microscope (STM) and selected area electron diffraction (SAED) results shown the single-crystalline nature of ULG. Transmission electron microscopy (TEM) shown the thickness of the panel was 3.5 nm and the thickness of the rib varied gradiently from 11.22 nm to 5.44 nm. The growth mechanism of the ULG was also explored by studying the influence of varied methane and hydrogen flow, which shows the ULG was formed during the nucleation stage. The larger flow of hydrogen supported decreasing the nucleation density of ULG, which was preferred for the formation of large domain ULG. Moreover, ULG partially immersed into liquid copper during the nucleation stage, thus, carbon atoms could reach each layer of ULG, leading to the continual growth of ULG graphene.Graphical abstractImage 1
       
  • MoS2 nanosheets inlaid in 3D fibrous N-doped carbon spheres for
           lithium-ion batteries and electrocatalytic hydrogen evolution reaction
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Xin Wang, Siming Fei, Shoushuang Huang, Chenghao Wu, Junru Zhao, Zhiwen Chen, Kajsa Uvdal, Zhangjun Hu Molybdenum disulfide (MoS2) has received considerable interests in rechargeable lithium-ion batteries (LIBs) and hydrogen evolution reaction (HER). To overcome the instinct limitations of pristine MoS2, such as low conductivity, poor cyclic stability and rate performance, hybrid carbon-MoS2 composites are often practically applied to improve the electrochemical properties. Herein, a facile, scalable, and durable synthesis method is innovated to inlay MoS2 nanosheets into three-dimensional (3D) fibrous nitrogen-doped carbon spheres (FNCs) for achieving 3D FNC-MoS2 composites. The free-standing 3D FNC-MoS2 nanocomposites can be used as the anode for LIBs. It exhibits a high reversible capacity of ∼700 mA h g−1, and nearly no fading of the capacity nearly after 400 cycles at a current density of 1.2 A g−1. Meanwhile, FNC-MoS2 exhibits superior HER activity accompanied by a small overpotential of around 194 mV in 0.5 M H2SO4. Tafel slopes are estimated to be 54 mV dec−1, and the current density of FNC-MoS2 decreases very slightly compared to the initial one after 1000 cycles. We are convinced that the enhanced Li+ storage performance and HER activity are attributed to the synergistic effects and structural advantages, such as higher specific surface, larger pore volume, radical fibrous structure, and chemical/mechanical stability, achieved from the unique architectures of the title material.Graphical abstractImage 1
       
  • Soft-confinement conversion of Co-Salen-organic-frameworks to uniform
           cobalt nanoparticles embedding within porous carbons as robust
           trifunctional electrocatalysts
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Fantao Kong, Xiaohong Fan, Xiaoying Zhang, Luyao Wang, Aiguo Kong, Yongkui Shan Co nanoparticles with about 10 nm particle size embedded in nitrogen-doped carbons (Co@NC) were successfully synthesized by a soft-confinement conversion strategy. A special Co(II)-Salen-organic framework was prepared as the precursor, which isolated a few Co(II) ions with thick aromatic polymer pore walls. These Co(II) ions were thermally converted into fine Co nanoparticles highly dispersing in porous nitrogen-doped carbons. The as-prepared Co@NCs showed efficient electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), together with better catalytic durability. In alkaline solution, the optimized Co@NC-800 exhibited a positive ORR half-wave potential (E1/2) of 0.85 V, superior to the benchmark Pt/C (E1/2 = 0.84 V). It also had a low overpotential (Eη) of 0.35 V at a current density of 10 mA cm−2 for OER, close to IrO2 (Eη = 0.36 V) catalysts. It could be also utilized as the outstanding air electrode materials in Zn-air batteries, which exhibited higher peak power density and cycling stability than Pt/C-based counterpart. By this unique soft-confinement conversion of Co(II)-Salen-COFs, the derived Co@NCs possessed the optimized local strcutures (high porosity and graphization degree) and the multiple active sites especially including high-density Co nanoparticle-activitated carbon layers, which contributed to their impressive trifunational electrocatalytic properities.Graphical abstractCo@N-doped carbons derived from newly-designed Co-Salen-organic-frameworks with open porous network exhibited efficient multifunctional electrocatalytic performance for oxygen transformation and water splitting.Image 1
       
  • Uniform coating of nano-carbon layer on SiOx in aggregated fluidized bed
           as high-performance anode material
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Zhexi Xiao, Chunhui Yu, Xianqing Lin, Xiao Chen, Chenxi Zhang, Fei Wei Carbon layer coating is a facile method to improve the electrochemical performance of SiOx. However, few strategies promise a uniform coating. The fluidized bed reactor with high heat and mass transfer efficiency to ensure uniform coating, requires large particles to achieve smooth fluidization. In this study, we bound the raw powders together to form loose secondary particles with a diameter of ∼100 μm, which were supposed to be both fluidized smoothly and also returned to their original size after carbon coating, to achieve a uniform carbon layer coating of ∼15 nm on commercial SiOx powders with a preferable graphitization degree (ID/IG = 1.0) and low surface area (∼2 m2 g−1). The SiOx@C composites delivered a high initial coulombic efficiency (75.1%), an excellent cyclability (83% capacity retention rate for 500 cycles at 1 A g−1), and a superior rate capability (907.7 mAh g−1 at 2 A g−1). The more than 106 increase in electronic conductivity and 104 increase in Li+ diffusion were responsible for the improvement of electrochemical performance. The resistance of the carbon layer to hydrogen fluoride (HF) erosion was observed. This method is suitable for the scaled-up production of anode materials and is expected to be applied to other materials.Graphical abstractImage 1
       
  • A high surface area N-doped holey graphene aerogel with low charge
           transfer resistance as high performance electrode of non-flammable
           thermostable supercapacitor
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Peng Xu, Qiuming Gao, Li Ma, Zeyu Li, Hang Zhang, Hong Xiao, Xiao Liang, Tengfei Zhang, Xuehui Tian, Chenhao Liu The high quality carbonaceous material with high surface area and low charge transfer resistance is vital for assembling the advanced supercapacitor. Herein, a novel kind of N-doped holey graphene aerogel (NHGA) is prepared. The NHGA has high specific BET surface area of 446 m2 g−1 and low charge transfer resistance of 0.4 Ω. A large specific capacity of 318.3 F g−1 is obtained at 0.5 A g−1 in a three-electrode configuration in 6 M KOH electrolyte, indicating the high capacity characteristic. As to the NHGA based symmetrical supercapacitor, the specific capacity of 96.0 F g−1 can be achieved at 200 A g−1, presenting its robust rate property. After 10,000 cycles at 2 A g−1, the specific capacity is 262.5 F g−1 with the capacity retention of 98.4%, showing its excellent cyclic stability. Notably, the energy density of 60.3 Wh kg−1 superior to that of the related typical reported supercapacitors, is obtained at the power density of 0.9 kW kg−1 in a non-flammable ionic liquid EMIMTFSI-80 electrolyte, which is effective from 20 to 100 °C. Thus, the advanced electrochemical property of NHGA is distinctly valuable for the supercapacitor utilization especially in the extremely conditions such as fire safety and/or high temperature.Graphical abstractImage 1
       
  • Miniemulsion polymerization using graphene oxide as surfactant: In
           situ
    grafting of polymer
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Yiting Cai, Yasemin Fadil, Florent Jasinski, Stuart C. Thickett, Vipul Agarwal, Per B. Zetterlund The occurrence of covalent grafting of polymer chains onto graphene oxide (GO) sheets during aqueous miniemulsion radical polymerizations of common vinyl monomers has been investigated. Styrene, benzyl methacrylate and t-butyl methacrylate were polymerized via miniemulsion polymerization using GO as sole surfactant, and the characterization of GO isolated post-polymerization was investigated by a range of experimental techniques (Fourier-Transform Near Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray Photoelectron spectroscopy (XPS), Raman spectroscopy and X-Ray Diffraction (XRD)). All experimental techniques show consistently that significant grafting occurs for all three monomers under these conditions. Furthermore, Raman spectroscopy indicated that the mechanism of grafting involves the sp2 carbons present in the GO structure, and not the oxygen-containing functional groups (e.g. epoxy, hydroxyl and carboxyl). The extent of grafting was quantified by XPS, revealing that polymer grafting occurred at levels in the approximate range of 20–60 wt% (grafted polymer relative to total mass of GO and grafted polymer). Miniemulsion polymerization using GO as surfactant is an attractive approach for synthesis of polymer/GO nanocomposites, and the present results are important in regards to the specific structures and performances of such materials.Graphical abstractImage 1
       
  • Ultra-strong nanographite bulks based on a unique carbon nanotube linked
           graphite onions structure
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Kunpeng Lin, Hailiang Fang, Feng Wen, Lianjun Wang, Wan Jiang, Jianlin Li Ultra-strong nanographite bulks have been prepared from nanodiamond (ND) particles doped with a small amount of carbon nanotubes (CNTs) by spark plasma sintering. The CNTs act as a guiding template to link the ND particles together successfully making the ND particles arranged approximately regularly and densely along the CNTs. During sintering, the NDs in situ transform into nanographite onions to form the unique “CNT-linked graphite onions” structure that bestows the as-prepared graphite bulks with ultra-high mechanical properties. With the CNTs contents ranging up to 20 wt%, the prepared bulk graphite with 5 wt% CNTs is found to have the highest bulk density and bending strength; its bulk density, microhardness, Young's modulus and bending strength achieve 1.78 g/cm3, 3.3 GPa, 20.7 GPa and 173.7 MPa, respectively. The bending strength is nearly 2 times the famous graphite (DS-4) which has reportedly the highest strength.Graphical abstractImage 1
       
  • Why some carbons may or may not graphitize' The point of view of
           thermodynamics
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Philippe Ouzilleau, Aïmen E. Gheribi, Patrice Chartrand, Gervais Soucy, Marc Monthioux Not all carbons graphitize in equal measure. Some will develop a structure which approaches the one of perfect graphite (graphitizable carbons) upon heat treatment, while others will not (non-graphitizable carbons). The present work develops a phenomenological model for the conceptual understanding of graphitizability (capacity to graphitize). To support this model, a mathematical formalism, inspired from thermodynamics, is proposed to calculate the Ultimate Graphitizability (ηg) of some graphitizable and non-graphitizable carbon materials. ηg is the average interlayer spacing (d002) of a graphenic carbon following graphitization at ∼3400K. ηg can be estimated assuming a topological graphitization mechanism operating between 1700K and 3400K. Two independent variables define ηg: d002(Tα) and d002(Tβ). Tα and Tβ are arbitrarily selected temperatures between 1700K and 2550K (the graphitization threshold). In order to better understand the parameters affecting d002(Tα) and d002(Tβ), new carbonization/graphitization experimental results are presented. These suggest that d002(Tα) and d002(Tβ) are correlated to the oxygen/hydrogen composition ratio and the relative mesoscale crystallite orientation of some graphitizable carbons following the end of primary carbonization.Graphical abstract
       
  • Nitrogen-doped CNT on CNT hybrid fiber as a current collector for
           high-performance Li-ion capacitor
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Sathya Narayan Kanakaraj, Yu-Yun Hsieh, Paa Kwasi Adusei, Bradley Homan, Yanbo Fang, Guangqi Zhang, Siddharth Mishra, Seyram Gbordzoe, Vesselin Shanov In this work, we describe a scalable synthesis process of binder-free, nitrogen-doped carbon nanotubes (CNTs) on CNT fibers combining a solvothermal process with chemical vapor deposition (CVD). Li4Ti5O12 was selected as an example active material to evaluate the performance of the obtained current collector electrode, which achieved 100% capacity retention after 1000 cycles at a 15C rate and a stable specific capacity of 144 mAhg−1 at 5C. We also report here the fabrication of an asymmetrical hybrid capacitor that exhibited a maximum specific energy of 0.296 mWhcm−2/0.019 Whcm−3/68 Whkg−1 at a specific power of 0.172 mWcm−2/0.011 Wcm−3/126 Wkg-1. It maintained specific capacitance of 0.0779 mWhcm−2/0.005 Whcm−3/17 Whkg−1 at a high specific power of 57.05 mWcm−2/3.719 Wcm−3/12,500 Wkg-1. The device exhibited a very stable cycling performance, retaining 100% of its specific energy after 2000 cycles at 4 Ag-1 current density. The increase in specific power, energy and cycling performance was attributed to the porous network afforded by the nitrogen-doped CNTs and their strong binding with the active material Li4Ti5O12. The porous network enabled fast Li-ion diffusion paths while the pristine CNT allowed for fast electron transfer all in a fiber format, making it attractive as an electrode for wearable energy storage devices.Graphical abstractScalable process of synthesizing meters of durable metal and binder-free amphiphilic CNT on CNT hybrid fiber current collector for high power density, potentially wearable battery application.Image 1
       
  • Orientation mapping of graphene in a scanning electron microscope
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Benjamin W. Caplins, Jason D. Holm, Robert R. Keller A scanning transmission electron diffraction method is developed for use in the scanning electron microscope to perform orientational characterization of 2D materials. The method can generate orientation maps of monolayer graphene over a field of view up to ≈50μm in just a few minutes and can distinguish twisted bilayers from aligned bilayers. This method holds promise to bring electron-diffraction-based orientation measurements of 2D materials to a broader audience.Graphical abstractImage 1
       
  • The regulation of the microstructure, luminescence and lubricity of
           multi-element doped carbon nanodots with alkylated diquaternary 1,
           4-Diazabicyclo[2.2.2]octane derived dicationic ionic liquids inserted in
           carbon skeleton
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Lina Zhao, Tao Cai, Mengting Ye, Dan Liu, Shenggao Liu Herein, carbon dots-ionic liquid (CDs-IL) hybrid nanoparticles are synthesized, on the one side, for constructing novel nanostructure with IL inserted into the carbon skeleton, on the other side, for integrating both excellent friction- and wear-reducing abilities. To realize the assumption, the 1,4-Diazabicyclo[2.2.2]octane was used as bridging agent to synthesize bis-functional dicationic ionic liquid with symmetric structure, followed by co-carbonization with carbon precursor to prepare target products under mild conditions. Three anions included bis(salicylato)borate (BScB), hexafluorophosphate (PF6) and bis(trifluoromethanesulphonyl)imide (NTf2) are utilized to tune their physicochemical properties. The chemical and microstructural properties of the products were characterized by NMR, FTIR, Raman mapping spectra, XPS, UV–visible spectra, Fluorescence spectra, SEM, HRTEM and so on. The produced CDs-IL with an average diameter range of 1–3 nm exhibit excitation-dependent maximum fluorescence at 340/405 nm, 440/518 nm and 380/458 nm for CDs-BScB, CDs-PF6 and CDs-NTf2, respectively. The CDs-PF6 is found to exhibit excellent anti-wear and friction-reducing properties as nanoadditives for PEG base fluid, which achieves remarkably improved anti-wear properties (96.5%) and friction-reducing (72.7%) properties simultaneously, owing to the formation of a protective carbon-based layer at the contact regions. Importantly, friction-induced luminescence quenching, transfer and aggregation of the CDs-IL were observed and their correlations were discussed.Graphical abstractImage 1
       
  • Carbon nanotubes grown on the inner wall of carbonized wood tracheids for
           high-performance supercapacitors
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Chenling Wu, Sen Zhang, Wei Wu, Zhaowei Xi, Cui Zhou, Xin Wang, Yuanyuan Deng, Yuanjuan Bai, Gonggang Liu, Xiang Zhang, Xianjun Li, Yongfeng Luo, Daoyong Chen Supercapacitors made by wood scraps are low cost, ecofriendly and accessible. However, there are some problems, such as a small specific surface area and low specific capacitance. How to obtain a high-performance supercapacitor by effectively increasing the specific surface area without affecting the conductivity is still a challenge. In this paper, carbon nanotubes (CNTs) were first synthesized on the inner wall of tracheids in wood carbon slices, which have complete structures and do not require any conductive additives and binder. Nanonickel particles as catalysts were uploaded on the inner wall of each tracheid for growing the CNTs, which can increase the specific surface area from 365.5 to 537.9 m2 g−1, while improving the electrochemical performance to 215.3 F g−1 or 76.5 F cm−3. The energy density of the all-solid-state supercapacitor is 39.8 Wh kg−1, and 96.2% of the capacitance could still be retained after 10,000 charging/discharging cycles. This capacitance value is approximately five times as high as that of activated wood carbon and is equal to or higher than that of supercapacitors based on wood carbon slices with pseudocapacitance materials. CNTs will greatly promote the application of wood scraps as valuable commodities.Graphical abstractImage 1
       
  • Preparation and property of extremely stable superhydrophobic carbon
           fibers with core-shell structure
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Shizhan Feng, Wanxia Luo, Luxiang Wang, Su Zhang, Nannan Guo, Mengjiao Xu, Zongbin Zhao, Dianzeng Jia, Xingchao Wang, Lixia Jia Superhydrophobic materials have a wide range of applications in oil/water separation, controlled corrosion and self-cleaning. However, most superhydrophobic polymer materials are surface-modified with fluorides or silicides, these materials will lose their superhydrophobic properties when exposed to strong acid, strong base or high temperatures. Herein, superhydrophobic carbon fibers (SCFs) with a core-shell structure have been prepared by electrospinning technology combined with subsequent chemical vapor deposition (CVD). The addition of oxidized coal (OC) increases the diameter of the fibers, while the CVD process achieves a graphitic carbon layer with low surface energy, ultimately resulting in a water contact angle (CA) as high as 159.5°. The as-prepared SCFs can effectively separate a series of oil/water mixtures with large flux and high separation efficiency. The SCFs have the ability to repel contamination of sand, orange juice, coffee and plant chlorophyll extract. What's more, the SCFs could maintain superhydrophobicity at the temperature of 97 °C under the corrosive liquid. In addition, the SCFs still maintain excellent superhydrophobicity after impregnating in strong acid, strong alkali and organic solvents for 120 days. The SCFs can be used repeatedly under various harsh conditions for a long time and may have a wide application prospect in the future.Graphical abstractImage 1
       
  • Enhanced gas barrier property of stacking-controlled reduced graphene
           oxide films for encapsulation of polymer solar cells
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Sae Jin Sung, Jisoo Park, Young Shik Cho, Se Hoon Gihm, Seung Jae Yang, Chong Rae Park Compact stacking of building blocks is essential in order to utilize the impermeable nature of reduced graphene oxide (rGO) for encapsulating barriers in organic electronics. To obtain the desired accumulation characteristic, rGO films were fabricated via spraying process using phase-controlled graphene oxide (GO) dispersion. The rGO laminate prepared from the isotropic-phase dispersion exhibits a more favorable face-on orientation of rGO building blocks than that from the nematic-phase GO, which implies effective stacking of building blocks. As a result, the resulting gas barrier performance of the low-temperature-annealed rGO film is superior to previously reported low-temperature solution-processed materials. Fabricated gas barriers are adopted to seal the polymer solar cell with 57.2 times longer lifetime than that of the unsealed device. A device covered by an optimized rGO/polyethylene naphthalate gas barrier maintains photovoltaic performance as high as 88% of the initial efficiency after 28 days.Graphical abstractImage 1
       
  • Enhancing the strength, toughness, and electrical conductivity of
           twist-spun carbon nanotube yarns by π bridging
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Xiumin Liang, Yuan Gao, Jianli Duan, Zunfeng Liu, Shaoli Fang, Ray H. Baughman, Lei Jiang, Qunfeng Cheng The weak interfacial interactions between carbon nanotube (CNT) always results in low stress load transfer efficiency in CNT yarns, herein we fabricated strong, highly conducting CNT yarns at room temperature using molecules having aromatic end groups, π bridging neighboring CNTs. The resulting CNT yarns have high tensile strength with 1697 ± 24 MPa, toughness with 18.6 ± 1.6 MJ/m3, and electrical conductivity with 656.2 S/cm, which are 3.9, 2.5, and 3.5 times, respectively, as high as that of the neat CNT yarn. The specific tensile strength of the resulting CNT yarn is higher than that for previously reported CNT yarns fabricated at room temperature, even that for some CNT yarns fabricated using corossive environments or extreme temperature. This π bridging strategy provides a promising avenue for fabricating high performance CNT yarns under ambient conditions.Graphical abstractThe new concept demonstrated in this work is applying π bridging strategy for constructing strong and highly conductive carbon nanotube yarns via interfacial design of π–π conjugated interaction. The π bridging strategy is very feasible and without any harsh conditions, providing an insightful approach for constructing high performance CNT yarns in the future.Image 1
       
  • The effect of physical adsorption on the capacitance of activated carbon
           electrodes
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Nathan L. Tolman, Jason M. Mukai, Shuqing Wang, Alessandra Zito, Tianyi Luo, Haitao Liu This work reports the effect of physisorption of organic compounds on the double layer capacitance of activated carbon electrodes. Exposure of activated carbon electrodes to toluene or chloroform vapor for less than 10 minutes resulted in a capacitance loss of 77% and 84%, respectively. Even adsorbates, such as acetone and ethanol, miscible with the aqueous Li2SO4 electrolyte caused 20–30% losses in capacitance. It was also found that there was an adsorbate size dependence: above a certain threshold, a larger adsorbate could have more than twice the impact on capacitance than a slightly smaller one. The results were consistent with the hypothesis that volatile organic contaminants (VOC) block access of the aqueous electrolyte to the carbon electrode surface. Porous activated carbon is currently the material of choice for supercapacitor electrodes in both research laboratories and commercial supercapacitor applications. These facilities also often house and use many volatile organic solvents either for research and development or simply for cleaning purposes. Because of this, our work has significant implications to the research and development of carbon-based supercapacitors.Graphical abstractImage 1
       
  • Free-standing graphene paper for energy application: Progress and future
           scenarios
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): R. Karthick, Fuming Chen The development of renewable energy sources minimizes the burning of fossil fuels for clean and green environment. Electrochemical energy storage/conversion device pays a way towards sustainable development that concludes an emerging field in the trends of the research community. Prominently, the functional materials with suitable structure and property determine the performance and durability of the devices. In recent times, graphene with its tremendous properties play a major role in electrochemical energy device applications. Meanwhile, the graphene-based electrodes were fabricated by various coating techniques on existing electrodes that utilized for energy device fabrication. Apart from these, it is also fabricated in a paper like a form (self-supported or free-standing) with its remarkable high conductivity, flexibility, robustness and electrochemical behavior which have been nominated for fabrication of flexible energy devices. Paper-like electrodes become an emerging field to fabricate a light-weight and flexible electronic devices for future prospects. Thus, we have summarized a synthetic strategy of graphene paper and its properties that potentially focused on flexible device fabrication in both the energy storage and conversion system. Hence, this review boosts up the forthcoming researchers to enhance the device performance with interrelating free-standing graphene and other host material.Graphical abstractNumber of publications from 2009 to 2018 based on free-standing graphene-paper in energy device applications gathered from Web of Science database search engine.Image 10612
       
  • Hydroxylated carbon nanotube/carbon nitride nanobelt composites with
           enhanced photooxidation and H2 evolution efficiency
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Hongfei Zhao, Shuaijun Wang, Fengting He, Jinqiang Zhang, Lin Chen, Pei Dong, Zhaoxin Tai, Yongqiang Wang, Haitao Gao, Chaocheng Zhao Hydroxylated multi-walled carbon nanotubes modified with a carbon nitride nanobelt (HCNT/CNN) were successfully fabricated by using combined solvothermal and ultrasonic methods to improve both tetracycline hydrochloride (TC) degradation and H2 evolution. The well-designed photocatalysts exhibited a wide light absorption range, low photoluminescence (PL) intensity, high photocurrent, and small electrochemical impedance spectroscopy (EIS) arc; these properties significantly enhanced the overall photocatalytic efficiency. At the optimal loading of HCNT (0.05 wt%), the resulting HCNT/CNN exhibited the highest TC photocatalytic degradation rate, and the H2 production rate reached 175.5 μmol g−1 h−1. Compared to the multi-walled carbon nanotube modified carbon nitride nanobelt, the TC photocatalytic degradation rate and H2 production rate of HCNT/CNN increased by factors of 3 and 4.2, respectively. This significantly enhanced performance can be ascribed to the formation of hydrogen bonds between HCNT and CNN, which facilitates the electron transfer from the CNN to the HCNT surface, thereby accelerating the separation of photogenerated charge carriers. Moreover, the possible mechanism of the improved photocatalytic performance for the HCNT/CNN composites was proposed. This study provides the guidance for the design of novel carbon nitride nanobelt-based photocatalysts for wastewater purification and H2 evolution.Graphical abstractGraphical Schematic illustration of a proposed mechanism for the HCNT/CNN composites.Image 1
       
  • Self-floating aerogel composed of carbon nanotubes and ultralong
           hydroxyapatite nanowires for highly efficient solar energy-assisted water
           purification
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Dong-Dong Qin, Ying-Jie Zhu, Fei-Fei Chen, Ri-Long Yang, Zhi-Chao Xiong Solar energy-driven water evaporation is a promising technique for clean water regeneration to tackle the world-wide water scarcity problem. Previous studies have revealed the important role of the bilayer structure in the solar energy-driven water evaporation, the top layer is the photothermal material, and the bottom porous material is used for water transportation and heat insulation. Herein, a new kind of the bilayer aerogel composed of hydrophilic ultralong hydroxyapatite (HAP) nanowire aergel and hydrophobic carbon nanotube (CNT) coating has been developed and demonstrated as a highly efficient self-floating evaporator for solar energy-driven photothermal water purification. The hydrophilic and highly porous HAP nanowire aerogel with a low thermal conductivity ensures excellent thermal management and high water evaporation rate, and the CNT coating layer enables highly efficient solar light absorption and energy conversion. With these structural merits, the as-prepared HAP/CNT bilayer aerogel has a high water evaporation rate of 1.34 kg m−2 h−1 and high water evaporation efficiency of 89.4% under solar light irradiation at a power density of 1 kW m−2. Additionally, the high-performance water purification function of the HAP/CNT bilayer aerogel is demonstrated by producing clean water from the actual seawater and simulated wastewater. The experimental results demonstrate the promising potential of the as-prepared HAP/CNT bilayer aerogel for high-performance solar energy-driven photothermal clean water regeneration.Graphical abstractImage 1
       
  • One-step eco-friendly synthesized silver-graphene oxide/poly(vinyl
           alcohol) antibacterial nanocomposites
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Mónica Cobos, Iker De-La-Pinta, Guillermo Quindós, M. Jesús Fernández, M. Dolores Fernández Due to the increasing occurrence and spread of antibiotic resistance pathogenic microorganisms, the development of antimicrobial materials has emerged as a strategy to control the bacterial activity and transmission. In this study, poly(vinyl alcohol)/silver nanoparticles-graphene oxide (PVA/AgNPs-GO) nanocomposites were synthesized by a one-step process with l-ascorbic acid as environmentally friendly reductant agent of a mixture of AgNO3, GO and PVA aqueous solutions. PVA/GO nanocomposites were also prepared for comparison. The structure, morphology, thermal, mechanical, water resistance and antibacterial properties of the samples were investigated as a function of GO and silver precursor contents. GO sheets decorated with spherical AgNPs were uniformly dispersed in the polymer matrix. The size range of most AgNPs was below 10 nm. Nanocomposites exhibited higher glass transition and crystallization temperatures. Thermal stability, mechanical and water resistance properties of PVA enhanced when GO was incorporated, and it was more remarkable in the presence of AgNPs-GO. PVA/AgNPs-GO nanocomposites showed antibacterial activity against Gram negative bacteria Escherichia coli and against Gram positive bacteria Staphylococcus aureus, being its efficiency dependent on exposure time and AgNPs precursor concentration. In contrast, PVA/GO films showed no activity against both bacteria over the GO loading range investigated. PVA/AgNPs-GO nanocomposites may be potential wound dressings.Graphical abstractImage 1
       
  • Structures of carbonaceous nanoparticles formed in various pyrolysis
           systems
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Helga Jander, Christine Borchers, Heidi Böhm, Alexander Emelianov, Christoph Schulz In the pyrolysis of different hydrocarbon/carbon suboxid fuels formation of carbon particles with the special view to their structures was examined. For this, the following three very different pyrolysis systems were investigated experimentally i) a pyrolysis reactor, ii) a shock tube and iii) a plasma reactor with respect to the influence of varying reaction parameters on the carbonaceous nanoparticles. The particles formed in these reaction systems were studied in view of their morphology and state of crystallization by use of electron microscopy (Philips CM30) at low- and high resolution combined with micro-diffraction measurements.As to be seen at low resolution of the transmission electron microscopy studies, the particle sizes in the pyrolysis reactor and shock tube do not differ significantly, but distinguished considerably from those particle sizes obtained in the plasma reactor. While the particles obtained in the pyrolysis reactor and shock-tube had particle diameters of about d≈ 30 nm, the particles in the plasma reactor consisted of fluffy-like units, and their sizes were about d≈ 4 nm. The various carbon layers consisted of different polyaromatic hydrocarbon units with variable sizes arranged to diverse states in the course of graphitization.Graphical abstractImage 1
       
  • Graphene based PANI/MnO2 nanocomposites with enhanced dielectric
           properties for high energy density materials
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Shatrudhan Palsaniya, Harshal B. Nemade, Ashok Kumar Dasmahapatra The high energy density materials driven by high storage permittivity are in huge demand due to their extensive applications in capacitors used in electric trains, hybrid electric vehicles, and aircraft. Nanocomposites, especially with conducting polymer exhibit characteristic properties such as well-organized framework, extensible, and rich dielectric strength, suitable for high-energy storage materials. The judicious choice of nanofillers for a given polymer matrix largely dictates the property enhancement in polymer nanocomposites. Herein, we explore GO, RGO and MnO2 as nanofillers to make binary (PANI-GO and PANI-RGO) and ternary nanocomposites (PANI-GO-MnO2 and PANI-RGO-MnO2) of PANI. The PANI-RGO-MnO2 ternary nanocomposite exhibits an excellent dielectric property owing to its hexagonal nanorods structure, as revealed by detailed morphological analysis. The in-situ polymerization of PANI ensures the formation of nanocomposites with uniform dispersion of MnO2 nanorods and RGO nanoflakes, which in turn yields high dielectric constant with excellent charge polarization. The frequency dependent study shows that the nanocomposites are quite stable over a long range of frequency, suitable for energy storage devices where high frequency is applied. The combination of high energy density with high breakdown strength indicates the potential applications of the nanocomposites in electrostatic capacitors and fabrication of high frequency dependent electronic components.Graphical abstractImage 1
       
  • An optimized graphene oxide self-assembly surface for significantly
           enhanced boiling heat transfer
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Wenbin Zhou, Lan Mao, Xuegong Hu, Yu He The enhancements in boiling heat transfer, i.e., critical heat flux (CHF) and heat transfer coefficient (HTC) can bring immediate benefits to improve the safety, efficiency and cost of heat energy transfer and conversion systems, leading to substantial global energy savings and reduction in greenhouse gas emissions. The enhanced boiling surfaces with great durability are highly desired for energy-intensive industrial applications. Here an optimized graphene oxide (GO) self-assembly surface for significantly enhanced boiling is developed, which could be readily fabricated utilizing the nucleate boiling self-assembly method. The optimal GO boiling surface produces remarkable improvements in boiling heat transfer performance (a CHF of 261 W cm-2 and a HTC of 9.1 W cm-2 K−1), which is among the highest values ever reported for pool boiling heat transfer on the planar enhanced surfaces. Additionally, it shows a good durability. The prominent performance can be attributed to the formation of interconnected and highly thermally conductive GO laminate film with moderate thickness on the substrate, which facilitates rapid cooling and rewetting of the local hot/dry regions, as well as bubble nucleation, thereby delay the occurrence of film boiling regime. The proposed strategy in current work is highly scalable and possesses enormous potentials in pragmatic applications.Graphical abstractImage 105882
       
  • On the effect of electric field application during the curing process on
           the electrical conductivity of single-walled carbon nanotubes–epoxy
           composites
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): M.V.C. Morais, A.I. Oliva-Avilés, M.A.S. Matos, V.L. Tagarielli, S.T. Pinho, C. Hübner, F. Henning Single-walled carbon nanotube (SWCNT)/epoxy composites were cured under external electric fields and the influence of the processing parameters (electric field magnitude and frequency, SWCNT concentration and curing temperature) on the electrical response of the system was evaluated. A mold for the electric field application was designed and manufactured, allowing in situ measurements of the electrical resistivity of the composite, during and after the curing process. The resulting electrical properties revealed a strong dependence on the processing parameters. By rising the curing temperature, the solid bulk resistivity was decreased by one order of magnitude. Further reduction was observed with electric fields, up to an additional order of magnitude. Such improvements can be related with the decrease in viscosity and improvement of interconnected-nanotube paths within the polymer matrix. The effect of the electric field on the rotation and interconnection of the SWCNTs was investigated using a classical mechanics model based on the dielectrophoretic theory for the liquid state. The influence of inter-nanotube distances on the bulk electrical properties was calculated at different particle concentrations, using finite element models of the microstructure. This processing technique presents promising results for enhancing the electrical conductivity of polymer composites with carbon-based nanoparticles.Graphical abstractImage 1
       
  • Structure evolution mechanism of highly ordered graphite during
           carbonization of cellulose nanocrystals
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Youngho Eom, Sung Min Son, Yea Eun Kim, Jung-Eun Lee, Sang-Ha Hwang, Han Gi Chae The microstructural evolution of highly ordered graphite during high temperature carbonization of cellulose nanocrystals (CNC) was traced in the temperature range of 1000–2500 °C. It was interesting to note that the direct carbonization of CNC under inert environment led to an irregular morphology due to molecular fusion whereas oxidative stabilization at 250 °C under air and subsequent carbonization preserved the pristine needle-like structure of the CNC during carbonization. Various characterizations such as high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) exhibited that the carbonization of CNC undergoes three distinctive stages of structural changes depending on carbonization temperature: (1) formation of turbo-stratic graphitic structure below 1500 °C (1st stage), (2) phase conversion to polycrystalline graphite between 1500 and 2000 °C (2nd stage), and (3) in-plane homogenization to highly ordered graphite above 2000 °C (3rd stage).Graphical abstractImage 100
       
  • Cherenkov polaritonic radiation in a natural hyperbolic material
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Jin Tao, Lin Wu, Guoxing Zheng, Shaohua Yu The existence of the forward and the reverse Cherenkov radiation for phonon polaritons (PhPs) in a natural hyperbolic material is theoretically demonstrated. It is shown that the forward and reverse Cherenkov polaritonic radiation can be simultaneously excited by an electron at a low velocity moving above a hexagonal boron nitride (hBN) layer within its upper and lower bands, respectively. The results show that the wavelength of polaritons radiation can be tuned by changing the thickness of the hBN layer and the radiation angles can be controlled by velocity of the moving electron. The proposed approach avoids the high velocity threshold of charged particle in conventional materials and complex fabrication of artificial metamaterials, opening a possibility of applications for polariton source, infrared spectroscopy and photonic integrated circuits, and offering a platform to investigate the light-matter interactions in nanoscale.Graphical abstractSchematic configuration for Cherenkov radiation of phonon polaritons with an electron traveling above a hBN layer.Image 1
       
  • Carbon nanotube micro-contactors on ohmic substrates for on-chip
           microelectromechanical probing applications at wafer level
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Mehmet O. Tas, Mark A. Baker, Vishal Musaramthota, Hasan Uppal, Mateus G. Masteghin, Jedidiah Bentz, Keir Boxshall, Vlad Stolojan CNTs can have the ability to act as compliant small-scale springs or as shock resistance micro-contactors. This work investigates the performance of vertically-aligned CNTs (VA-CNTs) as micro-contactors in electromechanical testing applications for testing at wafer-level chip-scale-packaging (WLCSP) and wafer-level-packaging (WLP). Fabricated on ohmic substrates, 500-μm-tall CNT-metal composite contact structures are electromechanically characterized. The probe design and architecture are scalable, allowing for the assembly of thousands of probes in short manufacturing times, with easy pitch control. We discuss the effects of the metallization morphology and thickness on the compliance and electromechanical response of the metal-CNT composite contacts. Pd-metallized CNT contactors show up to 25 μm of compliance, with contact resistance as low as 460 mΩ (3.6 kΩ/μm) and network resistivity of 1.8 × 10−5 Ω cm, after 2500 touchdowns, with 50 μm of over-travel; they form reproducible and repeatable contacts, with less than 5% contact resistance degradation. Failure mechanisms are studied in-situ and after cyclic testing and show that, for top-cap-and-side metallized contacts, the CNT-metal shell provides stiffness to the probe structure in the elastic region, whilst reducing the contact resistance. The stable low resistance achieved, the high repeatability and endurance of the manufactured probes make CNT micro-contacts a viable candidate for WLP and WLCSP testing.Graphical abstractImage 1
       
  • Gas-surface interactions of atomic nitrogen with vitreous carbon
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Vanessa J. Murray, Timothy K. Minton We have conducted beam-surface scattering experiments with the intent of identifying the reaction mechanisms that are relevant to the ablation of carbon by N atoms at surface temperatures relevant to hypersonic flight. A pulsed molecular beam containing N and N2 with translational energies of 460 and 808 kJ mol-1, respectively, was directed at a vitreous carbon surface held at temperatures in the range 1023–1923 K. Time-of-flight distributions were collected for scattered products with fixed incidence and final angles of θi = θf = 45°. Inelastically scattered N and N2 and reactively scattered CN were the only products observed. The scattering dynamics of N and N2 were independent of surface temperature and were indicative of purely impulsive scattering. The scattering dynamics of CN suggested that this reaction product is formed by a mechanism that occurs in thermal equilibrium with the surface – i.e., a Langmuir-Hinshelwood mechanism. The reaction probability to produce CN has an Arrhenius temperature dependence with an activation energy of 207 kJ mol-1. The relevance of the current results to the hypersonic ablation of carbon in the presence of dissociated air is discussed.Graphical abstractImage 1086731
       
  • A perspective on high-performance CNT fibres for structural composites
    • Abstract: Publication date: September 2019Source: Carbon, Volume 150Author(s): Anastasiia Mikhalchan, Juan José Vilatela This review summarizes progress on structural composites with carbon nanotube (CNT) fibres. It starts by analyzing their development towards a macroscopic ensemble of elongated and aligned crystalline domains, alongside the evolution of the structure of traditional high-performance fibres. Literature on tensile properties suggests that there are two emerging grades: highly aligned fibres spun from liquid crystalline solutions, with high modulus (160 GPa/SG) and strength (1.6 GPa/SG), and spun from aerogels of ultra-long nanotubes, combining high strength and fracture energy (up to 100 J/g). The fabrication of large unidirectional fabrics with similar properties as the fibres is presently a challenge, which CNT alignment remaining a key factor. A promising approach is to produce fabrics directly from aerogel filaments without having to densify and handle individual CNT fibres. Structural composites of CNT fibres have reached longitudinal properties of about 1 GPa strength and 140 GPa modulus, however, on relatively small samples. In general, there is need to demonstrate fabrication of large CNT fibre laminate composites using standard fabrication routes and to study longitudinal and transverse mechanical properties in tension and compression. Complementary areas of development are interlaminar reinforcement with CNT fabric interleaves, and multifunctional structural composites with energy storage or harvesting functions.Graphical abstractImage 10446
       
  • Facile synthesis of lightweight carbonized hydrochars decorated with
           dispersed ZnO nanocrystals and enhanced microwave absorption properties
    • Abstract: Publication date: Available online 12 May 2019Source: CarbonAuthor(s): Yujie Qi, Lin Qi, Liping Liu, Bushi Dai, Dongchao Wei, Gui-Mei Shi, Yang Qi Application of heterostructures in electromagnetic interference shielding application has been limited by the issue of the uniformly and dispersity of composites. Herein, we synthesized carbonized hydrochars/ZnO nanocrystals (CH/ZnO) composites via a strategy of expanding the interface of heterostructure. The introduction of dispersed ZnO nanocrystals leads to the emergence of the special heterostructure, associated with significant interfacial polarizations, resulting in an upgraded microwave absorption properties. It is demonstrated that the optimized reflection loss can achieve −49.24 dB with the thickness of merely 1.24 mm, and effective bandwidth (less than −10 dB) is ranging from 13.2 GHz to 16.6 GHz. The CH/ZnO composites in this work are outstanding microwave absorber with the merits of lightweight, easy preparation, wide source of raw materials and low cost.Graphical abstractImage 1
       
  • Fermi level shift in carbon nanotubes by dye confinement
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Y. Almadori, G. Delport, R. Chambard, L. Orcin-Chaix, A.C. Selvati, N. Izard, A. Belhboub, R. Aznar, B. Jousselme, S. Campidelli, P. Hermet, R. Le Parc, T. Saito, Y. Sato, K. Suenaga, P. Puech, J.S. Lauret, G. Cassabois, J.-L. Bantignies, L. Alvarez Dye confinement into carbon nanotube significantly affects the electronic charge density distribution of the final hybrid system. Using the electron-phonon coupling sensitivity of the Raman G-band, we quantify experimentally how charge transfer from thiophene oligomers to single walled carbon nanotube is modulated by the diameter of the nano-container and its metallic or semiconducting character. This charge transfer is shown to restore the electron-phonon coupling into defected metallic nanotubes. For sub-nanometer diameter tube, an electron transfer optically activated is observed when the excitation energy matches the HOMO-LUMO transition of the confined oligothiophene. This electron doping accounts for an important enhancement of the photoluminescence intensity up to a factor of nearly six for optimal confinement configuration. This electron transfer shifts the Fermi level, acting on the photoluminescence efficiency. Therefore, thiophene oligomer encapsulation allows modulating the electronic structure and then the optical properties of the hybrid system.Graphical abstractImage 1
       
  • Mass absorption cross-section of flare-generated black carbon:
           Variability, predictive model, and implications
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): B.M. Conrad, M.R. Johnson Global gas flaring is an important source of black carbon (BC) emissions with uncertain climate impacts. The link between atmospheric concentration and direct radiative forcing (DRF) by BC is its mass absorption cross-section (MAC). MAC data for flare-generated BC are lacking in the literature and the only known data conflict with generally-accepted BC MAC values, which are assumed to be source-independent. This paper presents the first measurements of BC MAC for large-scale flares, burning globally-representative, industry-relevant flare gas compositions in a controlled facility. BC MAC was calculated with precisely-quantified uncertainties using photoacoustic and thermal-optical instruments. Flare-generated carbon was found to be primarily elemental in composition (typically>92%), and most probably externally-mixed based on detailed analysis of attenuation vs. evolved carbon data and consideration of flare-specific mechanisms for organic carbon emissions. Flare BC MAC was generally larger than well-cited literature values and had statistically significant variations with fuel and operating conditions. Variability in BC MAC was well-predicted by a novel phenomenological model based on flame radiative characteristics and relative BC production. The derived model consolidates previously-unreconciled disparate data from different sources and suggests that flare BC MAC is likely>1.3–2 times standard values, implying an underestimation of DRF by flare-generated BC.Graphical abstractImage 1
       
  • Boosting Li–S battery by rational design of freestanding cathode with
           enriched anchoring and catalytic N-sites carbonaceous host
    • Abstract: Publication date: Available online 9 May 2019Source: CarbonAuthor(s): Zihao Bian, Tao Yuan, Ying Xu, Yuepeng Pang, Hongfei Yao, Jing Li, Junhe Yang, Shiyou Zheng Lithium-sulfur (Li–S) batteries are considered to be a promising energy storage owing to high energy density and low cost. However, the S cathodes are still suffering from poor cycle life and low Coulombic efficiency due to ‘shuttle effect’ of lithium polysulfide. Herein, we report a novel and effective strategy to fabricate a free-standing Li–S battery cathode with enriched anchoring and catalytic N-sites host. Benefiting from synergistic effects of multifunctional porous carbon nanofiber host (g-C3N4@PCNF), the g-C3N4@PCNF/S cathode achieves good flexibility and excellent cycling retention, such as stable long cycle performance with a capacity decay of only 0.056% per cycle over 500 cycles at 1.0 A g−1. The excellent performance of g-C3N4@PCNF/S cathode can be mainly attributed to: (i) the interconnected network and internal porous structure of PCNF offering free space for S-loading and volume change during charge/discharge; (ii) the 3D g-C3N4@PCNF host providing an efficient electron/Li+ transport highway for fast interfacial reaction kinetics; (iii) the catalytic effect of g-C3N4 promoting rapid redox conversion of S species and retarding polysulfide shuttling. This effective strategy has demonstrated great potential as good candidates for commercial flexible and durable Li–S batteries.Graphical abstractImage 1
       
  • Advanced Graphene@Sulfur composites via an in-situ reduction and wrapping
           strategy for high energy density lithium–sulfur batteries
    • Abstract: Publication date: Available online 9 May 2019Source: CarbonAuthor(s): Peng Yu, Zhi-Cao Xiao, Qian-Yu Wang, Jing-Ke Pei, Yan-Hua Niu, Rui-Ying Bao, Yu Wang, Ming-Bo Yang, Wei Yang Graphene/sulfur composite has been extensively studied for sulfur cathodes. However, a rapid and scalable fabrication of sulfur/graphene composite with advanced structures and functions is still a big challenge. Here, we report a unique solution-based strategy to simultaneously realize the reduction of graphene oxide (GO), the synthesis of elemental sulfur (S) and the effective packaging of S. In this strategy, the S firstly reacts with hydrazine hydrate and N, N-Dimethylformamide mixture, which generates a reductive sulfur-containing compound. When mixing this reductive sulfur-containing compound with GO dispersion, GO will be reduced and the reductive sulfur-containing compound will be oxidized to generate S. At the same time S will be well encapsulated inside highly wrinkled graphene layers because of the great interaction between graphene and sulfur through this method. Benefited from the unique packaging structures, the sulfur cathode demonstrates superior electrochemical performance in specific capacity, rate capability and cycling stability. A record high specific capacity of 705 mA h/g is realized at 2C even for a thick sulfur cathode with an areal density of 8.1 mg cm−2. This study brings a facile strategy for the fabrication of advanced sulfur/graphene composites with high energy and power densities.Graphical abstractImage 1
       
  • On the origin of mesopore collapse in functionalized porous carbons
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): En Zhang, Mirian Elizabeth Casco, Fei Xu, Wen-Bo Sheng, Steffen Oswald, Lars Giebeler, Karl Wegner, Lars Borchardt, Stefan Kaskel Heteroatom functionalization of ordered mesoporous carbon (OMC) represents an important strategy towards electrocatalytic and battery applications. Such functionalization frequently leads to degradation or even collapse of mesopores, which is generally attributed to the harsh conditions used or the successfully doped functional groups or the entrapment of guest species into mesopores. However, in this report, we find the structural deterioration of functionalized OMC is mainly induced by the water evaporation during the drying process, beyond the usually accepted concept mentioned above. We report two types of well-defined OMCs, resembling comparable pore architectures but varying in surface chemistry, namely the hydrophobic OMC (Cmeso) and hydrophilic one (HCmeso). After washing and drying processes, Cmeso remains intact regardless of the drying processes. In sharp contrast, HCmeso shows gradual porosity deterioration or even totally collapse under continuous washing-drying cycles. Lyophilization can however well preserve the porosity due to the reduced stress exerted by water on carbon walls. Such a distinct phenomenon is elaborately characterized by N2 physisorption, H2O physisorption, TEM and SAXS and further validated by well-known CMK-3, which undergoes surface functionalization by concentrated HNO3. Our finding reveals an important but neglected issue addressing the drying process in particular for polar functionalized porous carbons.Graphical abstractImage 1
       
  • Outstanding strength, optical characteristics and thermal conductivity of
           graphene-like BC3 and BC6N semiconductors
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Bohayra Mortazavi, Masoud Shahrokhi, Mostafa Raeisi, Xiaoying Zhuang, Luiz Felipe C. Pereira, Timon Rabczuk Carbon based two-dimensional (2D) materials with honeycomb lattices, like graphene, polyaniline carbon-nitride (C3N) and boron-carbide (BC3) exhibit exceptional physical properties. On this basis, we propose two novel graphene-like materials with BC6N stoichiometry. We conducted first-principles calculations to explore the stability, mechanical response, electronic, optical and thermal transport characteristics of graphene-like BC3 and BC6N monolayers. The absence of imaginary frequencies in the phonon dispersions confirm dynamical stability of BC3 and BC6N monolayers. Our first principles results reveal that BC3 and BC6N present high elastic moduli of 256 and 305 N/m, and tensile strengths of 29.0 and 33.4 N/m, with room temperature lattice thermal conductivities of 410 and 1710 W/m.K, respectively. Notably, the thermal conductivity of BC6N is one of the highest among all 2D materials. According to electronic structure calculations, monolayers of BC3 and BC6N are indirect and direct bandgap semiconductors, respectively. The optical analysis illustrate that the first absorption peaks along the in-plane polarization for single-layer BC3 and BC6N occur in the visible range of the electromagnetic spectrum. Our results reveal outstandingly high mechanical properties and thermal conductivity along with attractive electronic and optical features of BC3 and BC6N nanosheets and present them as promising candidates to design novel nanodevices.Graphical abstractImage 1
       
  • Influence of protons on reduction degree and defect formation in
           electrochemically reduced graphene oxide
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Javier A. Quezada-Renteria, Conchi O. Ania, Luis F. Chazaro-Ruiz, Jose R. Rangel-Mendez The electrochemical reduction of GO was investigated in aqueous, at both acid and basic pH, and organic media, to identify the possible role of protons (H+) in the reduction mechanism of this material. The obtained rGO films were characterized by FTIR, electrochemical methods, Raman and XPS spectroscopy. Data showed that the reduction was more efficient in acid and basic media due to the presence of protons and the capacity of water that works as a proton donor, resulting in C/O ratios of 3.8 and 7.8, respectively. Mostly hydroxyl, epoxide and carbonyl moieties were removed. In a proton-free organic electrolyte, a C/O ratio of 1.8 was obtained for most of the samples; nevertheless, the graphitic carbon sp2 domains were restored to a large extent in the absence of H+. The characterization of the material showed that the presence of protons, during the electrochemical reduction, caused hydrogenation reactions, which targeted the graphitic domains in rGO and resulted in the loss of sp2 hybridization. The presence of such defects modified the electrochemical properties of the rGO films, where, despite of exhibiting higher C/O ratio, the films reduced in aqueous electrolytes displayed lower electron transfer (e.g. ferrocyanide redox-probe) than those reduced in organic electrolyte.Graphical abstractImage 1
       
  • Densely integrated Co, N-Codoped Graphene@Carbon nanotubes porous hybrids
           for high-performance lithium-sulfur batteries
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Dongdong Cheng, Yelin Zhao, Xingwei Tang, Tong An, Xin Wang, Han Zhou, Di Zhang, Tongxiang Fan Design and synthesis of multifunctional sulfur hosts with comprehensively addressed conductivity, porosity and polarity is vital but challenging in the development of high-performance lithium-sulfur batteries. In this work, densely integrated Co,N-codoped graphene@carbon nanotubes porous hybrids (Co,N-G@CNT) are prepared as high-efficiency sulfur hosts for lithium sulfur batteries via reductive pyrolysis of (Co,Zn)-bimetallic zeolitic imidazolate frameworks separated graphene oxide sheets. The obtained Co,N-G@CNT possesses 3D interconnected conductive network, large nanopore volume and high accessible surface area as well as enriched doping sites, which endow the carbon matrix multifaceted abilities for sulfur accommodation and electron/ion transfer as well as polysulfides immobilization. Due to the rational structure design of the host material, the Co,N-G@CNT/S composite exhibits high sulfur utilization (1398 mA h g−1 at 0.2C), excellent rate capability (611 mA h g−1 at 6 C) as well as remarkable cycling stability (retained 659 mA h g−1 at 1C after 1500 cycles). This work provides a new perspective to function-directed structure design of sulfur hosts for lithium-sulfur batteries, and also holds great promise for the application in other energy storage/conversion systems such as metal air batteries, supercapacitors, and electrochemical catalysts.Graphical abstractImage 1
       
  • Effect of thermally decomposable spacers on graphene microsphere structure
           and restacking of graphene sheets during electrode fabrication
    • Abstract: Publication date: Available online 6 May 2019Source: CarbonAuthor(s): Jun Hui Jeong, Young Hwan Kim, Kwang Chul Roh, Kwang-Bum Kim Graphene has been proposed as a suitable material for electrodes in electrochemical double layer capacitors because of its excellent properties. However, a drawback is the irreversible restacking tendency of graphene during electrode preparation which, consequently, decreases the electrochemically accessible surface area. Therefore, to preserve the electrochemically accessible surface area of graphene, the development of controllable graphene structures with restacking-resistive property is highly desirable. In this work, spherical graphene with high restacking-resistive property during the re-dispersive process are synthesized using ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide as a decomposable spacer. During graphene assembly, the IL is not only used as a guide to obtain a spherical morphology, but also as a spacer that prevents restacking of graphene oxide (GO). Through our experiment, it was observed that, during the thermal treatment of spherical GO/IL to reduce GO to reduced graphene oxide (rGO), the IL could not only prevent restacking of GO sheets, but also protect its spherical morphology from the gas explosion generated by the reduction of GO. In particular, spherical rGO/IL has high surface area of 474 m2 g−1 and high restacking-resistive property such that it lost only 5% of its initial surface area after soaking in NMP, which exhibit high specific capacitance.Graphical abstractImage 1
       
  • Low content of Fe3C anchored on Fe,N,S-codoped graphene-like carbon as
           bifunctional electrocatalyst for oxygen reduction and oxygen evolution
           reactions
    • Abstract: Publication date: Available online 6 May 2019Source: CarbonAuthor(s): Zeyu Li, Qiuming Gao, Xiao Liang, Hang Zhang, Hong Xiao, Peng Xu, Zhengping Liu A novel kind of non-precious metal Fe3C@Fe,N,S-GCM nanocomposite with very low metal content is obtained by a simple one-pot pyrolysis method using abundent, low cost and environmental friendly resouces. In the Fe3C@Fe,N,S-GCM nanocomposite, the Fe3C nanoparticles are uniformly anchored on the Fe,N,S-codoped graphene-like carbonaceous matrix. Synergetic multiple electrocatalytic active sites of Fe3C, Fe-Nx and N,S-co-doped carbon are identified for Fe3C@Fe,N,S-GCM. The Fe3C@Fe,N,S-GCM nanocomposite also possesses the high BET surface area and meso/macropore volume from the hierarchical porous superstructure, which may benefit the storing and transport of electrolyte ions. Attributed to the rational content and microstructure, the Fe3C@Fe,N,S-GCM presents a high bifunctional electrocatalytic activity for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with the ΔE (= EOER - EORR) of only 0.750 V. The bifunctional electrocatalytic activity is not only better than the commercial precious metal couples of RuO2 (OER) and Pt/C (ORR), but also represents the superiority among the non-precious metal ferrous bifunctional electrocatalysts.Graphical abstractImage 1
       
  • Anomalous c-axis shifts and symmetry enhancement in highly oriented
           pyrolytic graphite at the magic angle
    • Abstract: Publication date: Available online 3 May 2019Source: CarbonAuthor(s): Filippo S. Boi, Mengjiao Liu, JiaChen Xia, Omololu Odunmbaku, Ayoub Taallah, Jiqiu Wen Observation of superconductivity in twisted-bilayer-graphene and highly-oriented-pyrolytic-graphite (HOPG) for certain magic-angles-of-rotation has recently attracted an important attention. Unusual temperature-(T)-induced-shifts in the graphitic c-axis have also been reported in HOPG in conditions of θ misfit ∼ 1° (first-magic-angle).We report a novel investigation of HOPGs with θ misfit of 0.5°, 0.8°, 1.5°, ≫ 1.5° and of water-treated-turbostratic-graphite in the T-range from 298.15 to 673.15K. Presence of magic angles of rotations corresponding to the reported θ misfit values is demonstrated by repeated HRTEM and Moiré pattern analyses of HOPG lamellae extracted from individual samples with scotch tape methods. Interestingly in our measurements the c-axis-shift is found to depend strongly on the misfit-angle, with the highest-values of 0.00428 and 0.00426 nm in proximity of the first-magic-angle (θ misfit ∼ 0.8° and ∼0.5°). Two diffraction-peaks present at ∼23.5° and ∼48.5° 2θ (detector angle, in typical Bragg- Brentano configuration) for θ misfit ∼1° are also found to vanish for θ misfit ≫ 1.5°. These findings imply existence of additional symmetry elements at the magic angle, which are not present in the standard space group notation used for structural characterization of graphite (P63/mmc).Graphical abstractImage 1
       
  • Metal-free core-shell structured N-doped carbon/carbon heterojunction for
           efficient CO2 capture
    • Abstract: Publication date: Available online 3 May 2019Source: CarbonAuthor(s): Ruilong Cai, Bo You, Min Chen, Limin Wu N-doped carbon/carbon heterojunction holds huge potential for efficient CO2 capture. Here, a series of site-specific N-doped core-shell carbon spheres with carbon/carbon heterojunction were successfully prepared by carbonization of polypyrrole coated hypercrosslinked polystyrene spheres, followed by chemical activation with KOH. These activated carbon spheres possessed large specific surface area (2080 m2 g−1) and abundant micropores (0.45 cm3 g−1). Despite their low nitrogen content (0.96 wt%), the CO2 adsorption capacities of activated samples reached 3.69 and 5.80 mmol g−1 measured at 298 and 273 K, respectively, under atmospheric pressure (1 bar). More significantly, the N-doped carbon/carbon heterojunction contributes to a stronger and denser CO2 packing in this system.Graphical abstractImage 1
       
  • Graphene interlayer for enhanced interface thermal conductance in metal
           matrix composites: An approach beyond surface metallization and matrix
           alloying
    • Abstract: Publication date: Available online 3 May 2019Source: CarbonAuthor(s): Huaijie Cao, Zhanqiu Tan, Ming-Hui Lu, Gang Ji, Xue-Jun Yan, Chen Di, Mengying Yuan, Qiang Guo, Yishi Su, Ahmed Addad, Zhiqiang Li, Ding-Bang Xiong Poor wettability and acoustic mismatch between diamond and copper cause low interface thermal conductance and thus low thermal conductivity in their composites. In this work, beyond widely used strategies such as surface metallization and matrix alloying, in-situ grown graphene is introduced as a highly effective interlayer. The positive role of graphene on improving wetting between diamond and copper was supported by the increase of relative density, fractured surface morphology and interface microstructure. Thanks to the improved wetting and mitigated acoustic mismatch between diamond and copper, the interfacial thermal conductance is increased by ∼3.7 times in the diamond/graphene/copper composite as indicated by differential effective medium calculation. Such a positive role of graphene interlayer also agrees with the results from the time-domain thermoreflectance measurements. As a result, the thermal conductivity of the diamond/graphene/copper composite is 61% higher than that of the counterpart without graphene interlayer. This study provides a new approach for interface modification by 2D materials for a high TC of diamond/copper composite beyond surface metallization and matrix alloying.Graphical abstractImage 1
       
  • Theoretical and Experimental Study on the Interfacial Adhesive Properties
           of Graphite Electrodes in Different Charging and Aging States
    • Abstract: Publication date: Available online 30 April 2019Source: CarbonAuthor(s): Zhansheng Guo, Chao Liu, Bo Lu, Jiemin Feng The present study consists in the development of an analytical model and the performance of 180° peeling tests aimed at evaluating the interfacial adhesive properties of graphite electrodes of lithium–ion batteries in different charging/discharging states. In order to determine the interfacial peeling strength, uniaxial tensile tests were conducted and an analytical model was used to obtain the elastic modulus of copper foil and the graphite active layer in different charging/discharging states. Results of the application of the interfacial peeling strength analytical model indicate that the interfacial peeling strength between graphite active layer and current collector does not depend exclusively on the energy release rate but also on the strain energy stored in the collector as a consequence of the expansion of the active layer associated with the insertion within it of lithium ions. The results of the 180° peeling tests indicate that the interfacial peeling strength of the fully charged electrode is larger than the corresponding parameters measured in the fresh, soaked, and fully discharged electrodes. The predictions based on the analytical model and the experimental data collected on the interfacial peeling strength are in good agreement with each other.Graphical abstractImage 107001
       
  • π-π stacking interface design for improving the strength and
           electromagnetic interference shielding of ultrathin and flexible
           water-borne polymer/sulfonated graphene composite
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Linfeng Wei, Wenbo Zhang, Jianzhong Ma, Shu-Lin Bai, Yanjuan Ren, Chao Liu, Demetra Simion, Jianbin Qin π-π stacking interface design strategy is proposed to prepare ultrathin and flexible water-borne polymer/sulfonated graphene nanosheets (S-GNS) composite by a facile self-assembly method in latex. The water-dispersible S-GNS was made by modifying the GNS with aryl diazonium salt. Styrene was introduced into water-borne polymer to form π-π stacking interaction with S-GNS. The composite shows good mechanical properties and high electromagnetic interference (EMI) shielding effectiveness (SE) in the X band (8.2–12.4 GHz). By Raman spectra, tensile tests, and simulation calculation, π-π stacking interaction is proved to be an effective interface bonding to enhance the mechanical properties. With a filler loading of 20 wt%, the tensile strength of composites is enhanced by 578%. The incorporation of 25 wt% S-GNS leads to a high EMI SE of 21.5 dB at 0.05 mm thickness, which remains unchanged after 1000 times bending. The specific SE/thickness (SSE/t) of the composite is as high as 2663 dB cm2/g, outperforming the ever reported materials with similar filler loading (25 wt%). The composite can be used as coating on the surfaces of solids, indicating the great potential for wide application.Graphical abstractImage 1
       
  • Porous Si/C microspheres decorated with stable outer carbon interphase and
           inner interpenetrated Si@C channel for enhanced lithium storage
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Zheng Yi, Yong Qian, Changhe Cao, Ning Lin, Yitai Qian The dual-functional carbons are decorated on porous Si microspheres with interpenetrated Si@C channel and stable outer carbon interphase, which are employed to boost the lithium storage and remedy the vital shortcomings of the Si anode, in terms of unstable solid−electrolyte interphase layer, terrible electronic conductivity, huge volume changes as well as bad cycling or rate capability. In this designed composite, the outer carbon layer can perfectly maintain the structure stability and avoid direct contact of Si with electrolyte during cycling, thus resulting in stable solid−electrolyte interphase film and improved initial coulombic efficiency. Furthermore, the inner carbon layer coated directly onto the porous Si framework can effectively enhance the overall conductivity, let the lithium insert fully and endow the composite with higher capacity in half and full cell. As a result, the as-prepared porous Si/C microspheres deliver a reversible capacity of 1660 mAh g−1 at 0.2 A g−1 after 100 cycles and 826.8 mAh g−1 at 2 A g−1 after 200 cycles.Graphical abstractDual-functional carbons are developed to remedy the vital shortcomings of the commercial Si anode, in terms of unstable solid−electrolyte interphase layer, terrible electronic conductivity, huge volume changes as well as bad cycling or rate capability.Image 1
       
  • Toward near-bulk resistivity of Cu for next-generation nano-interconnects:
           Graphene-coated Cu
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Hyo Chan Lee, Mankyu Jo, Hyungsub Lim, Min Seok Yoo, Eunho Lee, Nguyen Ngan Nguyen, Sang Youn Han, Kilwon Cho Recently, graphene has attracted much attention as a promising barrier material for Cu interconnection electrodes because of its excellent electrical, thermal, and mechanical properties and its ability to prevent the diffusion of Cu atoms. However, the effects of graphene on the electrical resistivity of graphene encapsulated Cu are still not fully understood. Here, we investigate the mechanism of electrical conduction in thin Cu films in contact with graphene. The contact of Cu with graphene layers was found to significantly reduce the resistivity of Cu thin films because it provides new current paths near highly resistive Cu grain boundaries. This effect became more prominent as charge-carrier mobility of graphene increased. In addition, we demonstrate that graphene encapsulation without performing any Cu engineering can ideally reduce the resistivity of Cu thin films by> 40%. The presence of graphene also significantly improves the stability of the electrical resistance of Cu thin films during bending.Graphical abstractImage 1
       
  • S doping coupled with pore-structure modulation to the conductive carbon
           black: Toward high mass loading electrical double-layer capacitor
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Xinlong Ma, Xinyu Song, Zhiqing Yu, Shengping Li, Xuejie Wang, Lu Zhao, Lei Zhao, Zhihua Xiao, Chuanlei Qi, Guoqing Ning, Jinsen Gao The conductive carbon black (CB) was modified by the pore-structure modulation and S doping in the presence of pore-modulation agent and S dopant via the one-step calcination methodology, resulting in the S-doped and pore-structure modified CB (labeled as SPCB). The conductivity and contact angle tests prove that the function of S doping can not only increase the electrical conductivity but also enhance the hydrophilicity. As electrode materials for symmetric electrical double-layer capacitor (EDLC), the influence of different mass loading of the electrode on the capacitive behavior is investigated. The areal mass loading of active materials for each electrode in the symmetric EDLC can reach up to 10 mg cm−2, comparable to the values of commercial devices. Without obvious sacrifice of the gravimetric capacitance is observed with the increase of mass loading, illustrating the small electrolyte ion transport resistance in electrode material and quick charge transfer property as well as the great compatibility for the gravimetric, areal and total capacitances. Additionally, the symmetric EDLC configured with SPCB affords the larger capacitance, better rate capability and higher capacitance retention as compared to the commercial activated carbon.Graphical abstractThe carbon black (CB) is modified by the one-step calcination methodology in which the pore-structure modulation and S doping are realized jointly, resulting in the S-doped and pore-structure modified conductive CB (labeled as SPCB). The areal mass loading of active materials for each electrode in the symmetric electrical double-layer capacitor (EDLC) can reach up to 10 mg cm−2, comparable to those of commercial devices. Additionally, the symmetric EDLC configured with SPCB affords the larger capacitance, better rate capability and higher capacitance retention as compared to the commercial activated carbon.Image 1
       
  • Local structures of nitrogen doped graphdiynes determined by computational
           X-ray spectroscopy
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Yong Ma, Juan Lin, Xiu-Neng Song, Chuan-Kui Wang, Weijie Hua, Yi Luo Nitrogen doping is an important method to modulate electronic structure of two-dimensional carbon materials. The properties of the doped systems are heavily dependent on the local structure of nitrogen dopants involved, which are often determined by experimental X-ray photoelectron spectra (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) at the nitrogen K-edge. In the present work, the N1s XPS and NEXAFS spectra of nitrogen-doped graphdiynes have been accurately calculated at the density functional theory level. Five representative nitrogen-dopants in graphdiynes, namely [pyridinic, amino, graphitic, and two sp-hybridized N (sp-N-1 and sp-N-2) local structures], are fully examined, from which all experimental features could be correctly assigned. The calculated results can be used to determine the ratio of different nitrogen dopants in graphdiyne at different elevated temperatures reported in previous experiments. Our findings provide the basic references for structure determination of nitrogen doped graphdiyne and new understanding of the underlying structure-property relationships.Graphical abstractImage 1
       
  • Murray's law-inspired approach towards highly graphitic carbons for
           electrocatalytic water splitting
    • Abstract: Publication date: Available online 4 May 2019Source: CarbonAuthor(s): Binghan Zhou, Mingchao Zhang, Wenya He, Haomin Wang, Muqiang Jian, Yingying Zhang Heteroatom doping in inert carbon matrixes has been widely adopted for efficient carbonaceous electrocatalysts. However, typical doping methods such as magnetic agitation and mechanical stirring may lead to a bad dispersion and thus poor reproducibility for electrocatalysis. Here, we proposed a strategy guided by the Murray's law to obtain hierarchically porous and highly graphitic carbons by cultivating rose flower in Ni(NO3)2 solution and pyrolyzing Ni-doped rose petals. The efficient Murray's network in the rose petals promotes uniform and sufficient transfer and absorption of Ni2+ ions, which later serve as catalyst sites for highly graphitic carbons at high temperature. Because of the enhanced crystallinity of carbon that promotes the smooth transfer of electrons and the uniformly embedded Ni nanoparticles in the carbon matrix that serve as electrocatalytic active sites, the as-obtained carbons show superior performance as a bi-functional electrocatalyst for efficient overall water splitting.Graphical abstractImage 1
       
  • Thermally etched porous carbon cloth catalyzed by metal organic frameworks
           as sulfur hosts for lithium–sulfur batteries
    • Abstract: Publication date: Available online 4 May 2019Source: CarbonAuthor(s): Yu Fu, Jing Hu, Qian Wang, Dongmei lin, Kaikai Li, Limin Zhou Activated carbon cloth (CC) plays vital roles in the fabrication of flexible energy devices, structured supports for catalysts, and CO2 capturer, etc. In terms of the conventional processing methods of activated CC, KOH and CO2 are the representative activation agents. Based on the idea of waiving the use of concentrated alkali and specialty gases, we demonstrate herein a highly efficient and previously unreported method of CC activation with a two-step procedure: homogeneous growth of metal organic frameworks (MOFs) on CC and subsequent activation catalyzed by the MOF derivatives. During pyrolysis, the MOF structures are transformed into Co3O4 particles, which react with carbon, leading to etching of the carbon fiber. This method can be used to form activated CC with coexistence of micropores, mesopores, and macropores. With the benefit of such hierarchical and unique structures, a free-standing sulfur-impregnated porous CC electrode demonstrates obvious advantages over CC-supported sulfur melt or sulfur slurry electrodes, which demonstrates great feasibility of MOF catalyzing porosification of CC for practical applications. This reported method not only broadens the scope of application of MOFs, it could also be further used to create hierarchical structures on other carbonaceous materials in various fields.Graphical abstractMetal organic framework derivatives-enabled facile fabrication of activated carbon cloth with hierarchical porous structures were successfully demonstrated. The prepared activated carbon cloth as a sulfur host demonstrated improved cycling performance in Li–S batteries, compared to its carbon cloth-based counterparts.Image 1
       
  • Highly efficient flame retardant and smoke suppression mechanism of boron
           modified graphene Oxide/Poly(Lactic acid) nanocomposites
    • Abstract: Publication date: Available online 4 May 2019Source: CarbonAuthor(s): Benjamin Tawiah, Bin Yu, Richard K.K. Yuen, Ruichao Wei, John H. Xin, Bin Fei Simultaneous flame retardancy and tensile strength enhancement of poly(lactic acid) (PLA) is particularly important due to its eco-friendliness and potential application as an engineering plastic. This work investigates the application of azo-boron (AZOB) modified reduced graphene oxide (RGO) intercalated by sodium metaborate (SMB) for simultaneous flame retardant (FR), smoke/toxic fumes suppression and tensile strength enhancement of PLA nanocomposites. The RGO-AZOB/SMB hybrid was prepared by aryl grafting of AZOB on GO followed by in-situ reduction/intercalation with sodium borohydride/SMB. Then RGO-AZOB/SMB hybrid was incorporated into PLA, and the properties were examined. Cone calorimeter test demonstrates improved FR performance by substantial reductions in peak heat release rate ∼76.5%, total heat release ∼76.9%, total smoke release ∼55.6%, peak CO production ∼25.9% and peak CO2 production by ∼78.6%. A V-0 rating was attained in the UL 94 test with a higher LOI value of 31.2%. Considerable reductions in pyrolysis products, mainly hydrocarbons, CO, CO2, and carbonyl compounds were observed. The tensile strength and Young's Modulus were improved by 49.1% and 34.9% respectively. The FR mechanism of RGO-AZOB/SMB/PLA nanocomposites is based primarily on the glassy charring effect of the B–OH groups in AZOB and the inherent lamellar blocking effect of RGO.Graphical abstractImage 1
       
  • A novel straightforward wet pulling technique to fabricate carbon nanotube
           fibers
    • Abstract: Publication date: Available online 3 May 2019Source: CarbonAuthor(s): Maria A. Zhilyaeva, Eugene V. Shulga, Sergey D. Shandakov, Ivan V. Sergeichev, Evgenia P. Gilshteyn, Anton S. Anisimov, Albert G. Nasibulin The growing demand for wearable electronics requires flexible and stretchable conductive materials. Among them, carbon nanotubes are recognized for their outstanding mechanical, electrical, optical properties and chemical stability. In this paper, we introduce a novel technique of carbon nanotube fiber fabrication, which we named Wet Pulling. The method allows straightforward fiber production out of carbon nanotube thin films, collected on a filter after the synthesis or deposited onto any substrate. It relies on a combination of film and solvent properties. The wet pulling technique has prominent advantages that make it a promising candidate for both small and large-scale production of CNT fibers with desired properties. The method is also easily adaptive to different kinds of carbon nanotubes and allows rapid fabrication of both active and passive flexible electronic components. A tactile sensor, a pulsometer and an electrical circuit are fabricated for the demonstration of their applicability. We expect this new approach to simplify the production of functional carbon nanotube fibers and to enlarge their usage in diverse applications.Graphical abstractA novel simple technique for CNT fiber fabrication out of CNT film is developed. Paving the way for novel flexible electronic devices, we studied and demonstrated the properties of the fibers. A tactile sensor, a pulsometer and an electrical circuit, made of SWCNT fibers, are presented as the illustration. This methodology is a promising way for rapid prototyping in the lab and potential roll-to-roll manufacturing.Image 1
       
  • Highly active metallic nickel sites confined in N-doped carbon nanotubes
           toward significantly enhanced activity of CO2 electroreduction
    • Abstract: Publication date: Available online 3 May 2019Source: CarbonAuthor(s): Wanzhen Zheng, Chenxi Guo, Jian Yang, Feng He, Bin Yang, Zhongjian Li, Lecheng Lei, Jianping Xiao, Gang Wu, Yang Hou Carbon dioxide electroreduction (CO2ER) still faces the challenges of low product selectivity, high overpotential, and high cost of electrocatalysts. Herein, we develop a low-cost and highly efficient precious-metal-free CO2ER electrocatalyst, composed of Ni nanoparticles (NPs) with the size range of 50–100 nm, confined within N-doped carbon nanotubes (NCNTs) with the diameter of 100–200 nm (Ni@NCNTs). Benefitting from the confinement effect, the resulting 1D Ni@NCNTs hybrid exhibits an exceptional electrocatalytic activity and selectivity for CO production with a relatively positive onset potential of −0.3 V, low Tafel slope of 97 mV dec−1, and high Faradaic efficiency of 99.1%. The high selectivity of Ni@NCNTs for CO production during the CO2ER is almost the best among all previously reported N-doped carbon based CO2ER electrocatalysts. Experimental observations demonstrate that the confined Ni NPs inside NCNTs is a key step to promote the conversion of CO2 to CO. Density functional theory calculations reveal that the confinement effect of NCNTs can weaken the binding strengths between Ni NPs and *CO intermediates, thus improving the rate-limiting step of *CO desorption during the CO2ER process. Further integration of 1D Ni@NCNTs electrocatalyst with a solar panel or two alkaline batteries enable highly active and sustainable CO2ER and water splitting.Graphical abstractImage 1
       
  • Facile preparation and capacitive properties of low-cost carbon nanofibers
           with ZnO derived from lignin and pitch as supercapacitor electrodes
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Seok In Yun, So Hyun Kim, Doo Won Kim, Yoong Ahm Kim, Bo-Hye Kim To develop economical and high-performance supercapacitor electrodes in an aqueous electrolyte, polyacrylonitrile (PAN)/pitch/lignin-based carbon nanofibers (CNFs) with ZnO (PPL-Zn) are successfully fabricated by one-step electrospinning of PAN, pitch, lignin, and zinc acetate. The oxygen-rich lignin in the PPL-Zn electrodes induces porosity on the fiber surface by eliminating many functional groups such carboxylic, carbonyl, hydroxyl and ketone and organic moieties in the simple heat treatment without any activation agent/activation process. Moreover, the many aromatic components, high carbon content, and low glass transition temperature of lignin are excellent precursors to CNF composites. In addition to lignin, pitch is used as a precursor to CNF to reduce the cost and increase the carbon yield and electrical conductivity of the CNFs. These characteristics afford PPL-Zn(5) (5 wt% of zinc acetate relative to PAN and lignin) with good capacitive behavior for application as supercapacitor electrodes with a maximum specific capacitance of 165 Fg-1 at 1 mAcm−2 with a capacitance retention of 88%, high energy densities of 22–18 Whkg−1 in the power density range of 400 to 10,000 Wkg-1, and excellent cycling performance reduced by only ∼6% after 3000 cycles of charge/discharge due to the synergistic effect of the electrical double layer and the pseudocapacitive effect.Graphical abstractImage 107
       
  • Glucose sensor based on porous Ni by using a graphene bottom layer
           combined with a Ni middle layer
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Zhaodi Ren, Haochao Mao, Haowen Luo, Yuanan Liu Porous nickel (pNi) was prepared by a hydrogen bubble template method by using a graphene bottom layer combined with a Ni middle layer on Cu foil substrate. The crystal structure and the pore size of the pNi were characterized by XRD and SEM, respectively. The TEM, SAED and XPS exhibited that the pNi and graphene as well as the Ni(OH)2 with high activity were formed on the surface. The glucose sensing performance in alkaline environments was estimated by cyclic voltammetry and chronoamperometry. The pNi as-prepared exhibits a high sensitivity of 6161μA/mM−1cm−2 within a linear range of 0.0005–1.0 mM, which is much better than that of pNi on Cu foil. The large quantities of active site supplied by the pNi with pore size as low as 1–15 μm as well as the high electron transfer ability between electrode and active reaction center induced by the graphene play important roles in obtaining the pNi as-prepared with high sensitivity and a broad linear range. It provides a new idea for the development of non-enzymatic glucose sensor especially based on porous Ni with graphene bottom layer and Ni middle layer.Graphical abstractImage 1
       
  • Precise controlling of positive and negative Goos-Hänchen shifts in
           graphene
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Xiang Zhou, Shuoqing Liu, Yiping Ding, Li Min, Zhaoming Luo We study the Goos-Hänchen (GH) effect in a graphene-substrate system comprehensively by using the transfer matrix method. It is revealed that the magnitude and sign of GH shifts are closely related to the imaginary part of graphene conductivity in the case of the fixed refractive index of substrate, while the Brewster angle position is largely influenced by the real part of conductivity. Further studies show that the position of Brewster angle keeps invariable when the Fermi energy exceeds 0.4 eV, and the magnitude and sign of GH shifts at a certain Brewster angle are changed only by Fermi energy. On the basis of these findings, a scheme to control the positive and negative GH shifts precisely is proposed and demonstrated by instances. We first adjust the refractive index of substrate to control the Brewster angle position under the condition of the Fermi energy exceeding 0.4 eV, and then adjust the Fermi energy to make the GH shift approach target value. Finally, we apply these precise control properties of GH shift to design a refractive index detector with adjustable sensitivity coefficient. These researches may have potential applications in refractive index sensor with high sensitivity and precise measurement of graphene parameters.Graphical abstractImage 1
       
  • Branched polyelectrolyte grafted carbon dots as the high-performance
           friction-reducing and antiwear additives of polyethylene glycol
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Zihao Mou, Baogang Wang, Hongsheng Lu, Hongping Quan, Zhiyu Huang Branched polyethyleneimine (PEI) grafted carbon dots (CDs-PEI0.6-10k) were facile synthesized by hydrothermal treatments of citric acid and PEI with various molecular weights of 0.6, 1.8 and 10 k. With the aid of protonation and anion exchange (between Cl− and bistrifluoromethanesulfonimide abbreviated as NTf2-) processes in aqueous phase, the branched polyelectrolyte grafted CDs (CDs-PEI0.6-10k-NTf2) derived from CDs-PEI0.6-10k were gained as the precipitates. The tribological properties of CDs-PEI0.6-10k-NTf2 as the lubricant additives of polyethylene glycol (PEG200) were evaluated. The CDs-PEI0.6-10k-NTf2 exhibited superb friction-reducing and antiwear performances followed the sequence: CDs-PEI10k-NTf2 > CDs-PEI1.8k-NTf2 > CDs-PEI0.6k-NTf2. Typically, the friction coefficient and wear volume of PEG200 reduced by 53.8% and 79.9%, respectively, when only 0.07 wt% of CDs-PEI10k-NTf2 was introduced. The surface analysis results revealed that a tribochemical reaction film composed of iron compounds (including iron fluorides, sulfates, nitrides, oxides and carbides) and organic compounds containing various elements (such as C, O, N, S and F) should form on the rubbing surfaces lubricated by CDs-PEI10k-NTf2 (0.07 wt%)/PEG200 dispersion. The distinguished friction-reducing and antiwear properties of CDs-PEI10k-NTf2 could be attributed to their nanolubrication effects and the above tribochemical film, i.e. the synergistic lubrication effect of their carbon cores and surface groups.Graphical abstractImage 1
       
  • Twisted graphene nanoribbons as nonlinear nanoelectronic devices
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): M. Saiz-Bretín, F. Domínguez-Adame, A.V. Malyshev We argue that twisted graphene nanoribbons subjected to a transverse electric field can operate as a variety of nonlinear nanoelectronic devices with tunable current-voltage characteristics controlled by the transverse field. Using the density-functional tight-binding method to address the effects of mechanical strain induced by the twisting, we show that the electronic transport properties remain almost unaffected by the strain in relevant cases and propose an efficient simplified tight-binding model which gives reliable results. The transverse electric field creates a periodic electrostatic potential along the nanoribbon, resulting in a formation of a superlattice-like energy band structure and giving rise to different remarkable electronic properties. We demonstrate that if the nanoribbon geometry and operating point are selected appropriately, the system can function as a field-effect transistor or a device with nonlinear current-voltage characteristic manifesting one or several regions of negative differential resistance. The latter opens possibilities for applications such as an active element of amplifiers, generators, and new class of nanoscale devices with multiple logic states.Graphical abstractImage 1
       
  • 3D/2D direct Z-scheme heterojunctions of hierarchical TiO2
           microflowers/g-C3N4 nanosheets with enhanced charge carrier separation for
           photocatalytic H2 evolution
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Juan Wang, Guohong Wang, Xiao Wang, Yao Wu, Yaorong Su, Hua Tang Constructing a 3D/2D direct Z-scheme heterojunction is a practical way to promote charge separation for attaining efficient solar hydrogen production. In the present work, hybrid 3D TiO2 microflowers/2D g-C3N4 nanosheets with a direct Z-scheme heterostructure is designed and fabricated through a hydrothermal and calcination process. The photocatalytic properties of the hybrid photocatalysts are evaluated by water splitting under solar light irradiation. The optimal ratio of g-C3N4 in the hybrid is found to be 50% (wt), and the resulting TiO2/g-C3N4 composite shows the highest photocatalytic activity among the experimental samples, which is 7.7 and 1.9 times higher than that of bare g-C3N4 and TiO2, respectively. The outstanding H2 production activity benefits from the synergistic effects of highly dispersed 3D TiO2 microflowers, extended photo-response to visible light through coordinating with 2D g-C3N4 nanosheets and the strong coupling effect resulting from an efficient direct Z-scheme structure. Photoluminescence and photocurrent response results reveal that the photoinduced e−-h+ pairs in this 3D/2D direct Z-scheme heterojunction can be separated efficiently, which also accounts for the obtained outstanding performance. Our results suggest that constructing a 3D/2D Z-scheme heterojunction in photocatalysts could be an efficient way to realize high speed solar H2 production.Graphical abstractImage 10669
       
  • Mold-casting prepared free-standing activated carbon electrodes for
           capacitive deionization
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Linlin Wu, Mingquan Liu, Silu Huo, Xiaogang Zang, Min Xu, Wei Ni, Zhiyu Yang, Yi-Ming Yan Activated carbon (AC) electrodes applied in capacitive deionization (CDI) are usually prepared by coating activated materials on current collector, accompanying with low mass loading, poor areal salt adsorption capacity (SACA) and undesired volumetric salt adsorption capacity (SACV). Herein, we report preparation of free-standing AC electrodes by a simple mold-casting method. Unlike conventional coating methods, activated materials were well-dispersed together with binders to obtain a uniform suspension and then submitted for mold-casting preparation of electrodes. This new strategy helps to produce rational structure for porous free-standing AC electrodes by alleviating the blocking effect of pores. Obtained electrodes not only exhibit pretty good electrical conductivity and hydrophilicity, but also show excellent mechanical stability and water tolerance. The electrodes deliver both high SACA of 0.49 mg/cm2 and SACV of 2.48 mg/cm3. By virtue of the free-standing feature, a CDI device comprising 6 as-made units was built for demonstration, which exhibits a promising SACV of 2.01 mg/cm3 in NaCl aqueous solution. This work not only offers a simple method to prepare free-standing AC electrodes with extraordinary high mass loading (55 mg/cm2) and excellent salt adsorption capacity, but also provides good opportunity for large-scale application of CDI technology by substantially improving packing volumetric density.Graphical abstractImage 1
       
  • Strengthening and toughening by partial slip in nanotwinned diamond
    • Abstract: Publication date: Available online 3 May 2019Source: CarbonAuthor(s): Bo Yang, Xianghe Peng, Cheng Huang, Zhongchang Wang, Deqiang Yin, Tao Fu It was reported recently that synthesized nanotwinned diamond (nt-diamond) possesses unprecedented hardness and ductility, however, the role of nanotwins in strengthening and toughening mechanisms remains unclear. In this article, we compared the atomic reconfiguration patterns of nt-diamond and nt-Si obtained with first principles calculations. We found that the detwinning in nt-diamond, which can be achieved by partial slip on the glide-set plane, could account for the strengthening of nt-diamond. Such continuous partial slip could lead to an extremely large increase in strain range and intragranular deformation resistance for nt-diamond. In contrast, the stress of nt-Si could be released by the slip on the shuffle-set plane, which could not induce detwinning. Different responses in nt-diamond and nt-Si can be accounted for with their generalized stacking fault energies (GSFEs). The glide-set plane in diamond has lower GFSE, therefore, the atoms would slide preferentially along the glide-set plane; while in Si, the shuffle-set plane has lower GFSE. These results can provide insights into the atomic reconfiguration as well as the unprecedented strength and ductility of nt-diamond under shear deformation.Graphical abstractThe schematic diagram of different deformation mechanisms of nt-diamond and nt-Si under large strain. Light-yellow regions correspond to the twinned region.Image 1
       
  • Bulk synthesis of graphene-like materials possessing turbostratic graphite
           and graphene nanodomains via combustion of magnesium in carbon dioxide
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Tak H. Kim, Christopher R. Merritt, Caterina Ducati, Andrew D. Bond, Nick Bampos, Christopher L. Brown This study reports a gram scale synthesis of a turbostratically aligned carbon material containing regions of graphite and few-layer graphene located in carbon-only nanodomains. The material, obtained from the combustion of magnesium in a carbon dioxide atmosphere, displays 2D and layered 3D molecular architectures. Of particular interest is that the introduction of an in-air high-temperature calcination process yields a carbon material possessing discrete turbostratic structural regions, as evidenced by Raman spectroscopy, transmission electron microscopy, electron energy loss spectroscopy and X-ray powder diffraction characterisations.Graphical abstractImage 1
       
  • Self-assembly carbon dots for powerful solar water evaporation
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Qiao Hou, Chaorui Xue, Ning Li, Huiqi Wang, Qing Chang, Hantao Liu, Jinlong Yang, Shengliang Hu Solar-driven water vaporization is considered one of the most sustainable technologies to solve water scarcity. However, the advanced design solar absorber system is still required for highly efficient steam generation. Here we develop a novel system for water evaporation through assembly of carbon dots within microchannels of processed wood. Not only is a dual-layer structure including of heat barrier and water transport channel formed, but also the modulation of carbon dot energy structures in favor of photothermal conversion is realized synchronously. This system exhibits higher water evaporation rate and energy efficiency for solar to steam generation than other black photothermal sheets (e.g. carbon nanotube, graphene, graphene oxide). On the one hand, the constructed size-dependent vaporization enthalpy theory shows that the micropores are beneficial to reduce vaporization enthalpy of water. On the other hand, the presented direct evidences for the roles of oxidation functional groups in solar thermal evaporation demonstrate that hydroxyl groups can improve solar-to-heat efficiency. Therefore, tailoring pore sizes and surface functional groups could be an efficient method for solar-to-vapor systems.Graphical abstractSolar-driven water vaporization system fabricated with carbon dots achieved solar-to-steam efficiency of 92.7% with an impressive evaporation rate of 2.27 kg m−2 h−1 under one sun irradiation.Image 1
       
  • Influence of oxide substrates on monolayer graphene doping process by
           thermal treatments in oxygen
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Angelo Armano, Gianpiero Buscarino, Marco Cannas, Franco Mario Gelardi, Filippo Giannazzo, Emanuela Schilirò, Raffaella Lo Nigro, Simonpietro Agnello The structural and the electronic properties of monolayer graphene made by chemical vapor deposition and transferred on various oxide substrates (SiO2, Al2O3, and HfO2) are investigated by Raman Spectroscopy and Atomic Force Microscopy in order to highlight the influence of the substrate on the features of p-doping obtained by O2 thermal treatments. By varing the treatment temperature up to 400 °C, the distribution of the reaction sites of the substrates is evaluated. Their total concentration and the consequent highest doping available is determined and it is shown that this latter is linked to the water affinity of the substrate. Finally, by varing the exposure time to the gas up to 2 h, the kinetics of doping is investigated. The doping process is found to be better described by a diffusion limited kinetic model, ascribable to the diffusion of O2 in the interstitial space between graphene and the substrate. After this step, the doping process is completed by a faster redox reaction between O2 adsorbed to graphene and interstitial H2O.Graphical abstractImage 1
       
  • In-situ preparation of nitrogen doped unimodal ultramicropores carbon
           nanosheets with ultrahigh gas selectivity
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Ning Fu, Jing Yu, Jing Zhao, Rui Liu, Feng Li, Yuchuan Du, Zhenglong Yang The development of simple and feasible methods to synthesize highly efficient adsorbents is the key to low-cost gas purification. Here we developed an in-situ amorphous cobalt template method based on the synergistic effect of precursor to synthesize nitrogen doped unimodal ultramicropores carbon nanosheets Co-NDPCs with high nitrogen content (up to 11.74%), large specific surface area (up to 1187 m2 g−1) and unimodal ultramicropore. As an adsorbent, the Co-NDPCs exhibit unprecedented C2H2, C2H6, C3H8 and CO2 uptake capacities of 6.7, 5.9, 7.4 and 5.6 mmol g−1, respectively, and the corresponding x/CH4 and CO2/N2 IAST selectivities are as high as 75.3, 65.9.1743.6, 11.4 and 74.7 at 298 K and 1 bar. More importantly, this method effectively avoids the defects of traditional activation or template method, such as corrosiveness, poor safety and complicated process, indicating that Co-NDPCs is a promising adsorbent for CH4/C2H2/C2H6/C3H8/CO2/N2 capture and separation.Graphical abstractImage 1
       
  • BC2N monolayers as promising anchoring materials for lithium-sulfur
           batteries: First-principles insights
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Yangfan Shao, Qian Wang, Liang Hu, Hui Pan, Xingqiang Shi One of the major challenging issues in lithium-sulfur (Li-S) batteries is that the lithium polysulfides easily dissolve in the electrolyte and shuttle between anode and cathode. To overcome this problem, an ideal anchoring materials is urgent. In the current work, we explore the potential application of BC2N allotropes (approximated by Type-I and Type-II structures) as anchoring materials for Li-S batteries by using first-principles method with van der Waals interaction. Type-I is a direct-bandgap semiconductor, while type-II is semi-metallic due to inversion symmetry of its structure. They show remarkable but not too strong chemical interaction with S8 and Li2Sx clusters and enhanced electrical conductivity. In addition, the introduction of dopants and defects result in semiconductor-to-metal transition on type-I BC2N, and enhancement of binding energies and still keep intact Li2Sx clusters. Our findings demonstrate that defective and doped BC2N monolayers are promising anchoring materials for Li-S batteries.Graphical abstractImage 1
       
  • Measurement of organic carbon content during the growth soot particles in
           propane normal and inverse diffusion flames using a multi-wavelength light
           extinction method
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Sangchul Lim, Seunghoon Lee, Taekook Ahn, Sunho Park This paper proposes a novel method for in situ determination of the organic carbon (OC) content in soot particles using a multi-wavelength light extinction method for propane normal diffusion flames (NDFs) and inverse diffusion flames (IDFs). Light extinction at wavelengths of 450–900 nm was measured using white light and a spectrometer. The light extinction coefficient plotted as a function of the reciprocal wavelength revealed the extinction characteristics of the soot particles. Additionally, the wavelength dependency of the OC content in soot was determined using the ratio of the slopes at short and long wavelengths. For the NDF, the slope ratio was higher near the flame center and upstream of the flame, whereas for the IDF, a constant of slope ratio was observed in all measurement positions. By comparing the slope ratio with the soot component analysis, a quantitative relationship was derived between the organic mass fraction (OMF) of the soot and the slope ratio. The OMF was 0.1–0.27 depending on the position in the NDF, and the IDF showed a similar OMF of 0.25–0.32 at all measurement positions. The results of transmission electron microscopy and electron energy loss spectroscopy also confirmed the validity of the OMF measurement.Graphical abstractImage 1
       
  • Molecular characterization of macroscopic aerogels of single-walled carbon
           nanotubes
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Belén Alemán, Juan J. Vilatela Single-walled carbon nanotubes (SWCNT) can be assembled into various macroscopic architectures, most notably continuous fibers and films, produced currently on a kilometer-per-day scale by floating catalyst chemical vapor deposition and spinning from an aerogel of CNTs. An attractive challenge is to produce continuous fibers with controlled molecular structure with respect to the diameter, chiral angle and ultimately (n,m) indices of the constituent SWCNT “molecules”. This work presents an extensive Raman spectroscopy and high-resolution transmission electron microscopy study of SWCNT aerogels produced by the direct spinning method. By retaining the open structure of the SWCNT aerogel, we reveal the presence of both semiconducting and metallic SWCNTs and determine a full distribution of families of SWCNT grouped by optical transitions. The resulting distribution matches the chiral angle distribution obtained by electron microscopy and electron diffraction. The effect of SWCNT bundling on the Raman spectra, such as the G− line shape due to plasmons activated in the far-infrared and semiconductor quenching, are also discussed. By avoiding full aggregation of the aerogel and applying the methodology introduced, rapid screening of molecular features can be achieved in large samples, making this protocol a useful analysis tool for engineered SWCNT fibers and related systems.Graphical abstractImage 1
       
  • Graphene quantum dot arrays: Pros and cons of photodetection in the
           Coulomb blockade regime
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Abid, Poonam Sehrawat, S.S. Islam Photon detection at elevated temperatures is a long-term debatable issue. Efforts are on to extend the temperature range beyond RT and this has been accomplished to a certain extent by combining two factors –(i) device’ structural design, and (ii) degree of quantum confinement. Zero-dimensional quantum confined semiconductor heterostructures have been investigated both theoretically and experimentally for quite some time; but no reports are available whether Quantum Dots is worthy for photodetection in Coulomb blockade regime and possess, if any, virtue to extend the operating temperature.In this report, Graphene Quantum Dots array (GQDs), were subjected to detect high photon density in the temperature range 77–623 K to check the sustainability of its noise free and quality performance. Stable performance is found up to 530 K beyond which the detector performance got badly affected owing to carrier transport and relaxation mechanisms. Appreciable detection performance is found in the Coulomb blockade (CB) regime (93–138 K) where carrier charging and tunneling through QDs control the detection mechanism. In non-CB regime (138–623 K), normal activation energy induced photodetection takes place. Detector performance shows that the user can opt for both the temperature regimes, though there are marked differences between them in terms of detection mechanism and performance.Graphical abstractImage 1012
       
  • Direct assembly of micron-size porous graphene spheres with a high density
           as supercapacitor materials
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Jie Wei, Chong Luo, Huan Li, Wei Lv, Jiachen Liang, Yaqian Deng, Zhijia Huang, Cong Wang, Feiyu Kang, Quan-Hong Yang A high volumetric energy density is extremely important in practical energy storage devices. Porous yet dense graphene monoliths obtained from a graphene hydrogel by capillary shrinkage are promising materials for achieving both high volumetric power and energy densities but they are hard to be further processed or ground into fine powders for use in industrial electrode fabrication. Here, by introducing an additional shaking process during the assembly, the bulk graphene hydrogel was broken into many graphene spheres of a much smaller size, and after capillary drying, micron-size graphene spheres were obtained with both a high density and high porosity. These microspheres were used to assemble an electrode with a higher density and give an improved volumetric energy density, which is very important for practical energy storage devices.Graphical abstractImage 1
       
  • FeOF nanoparticles wrapped in graphitic carbon layers in situ prepared
           from Fe-MIL-88B as a cathode material for sodium-ion batteries
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Maulana Achmad Yanuar, Jongsik Kim Sodium-ion batteries (SIBs) are considered a promising alternative for lithium-ion batteries because of the abundance and economic benefits of sodium. Iron oxyfluoride (FeOF) is attractive as a cathode material for SIBs because of its high theoretical capacity (∼855 mA h g−1), low cost, and environmental friendliness. However, FeOF often suffers from poor rate capability and cycling stability because of its low electronic conductivity and ion diffusion coefficient. In this work, we synthesize FeOF nanoparticles wrapped in graphitic carbon layers in situ prepared from an Fe-containing metal organic framework, Fe-MIL-88B. The FeOF electrode exhibits excellent cycling performance with reversible capacities above 338 mA h g−1 at the 100th cycle and a current density of 100 mA g−1. In addition, the rate capability is significantly improved in comparison with that of FeOF alone.Graphical abstractImage 1
       
  • Probing carrier concentration in gated single, bi- and tri-layer CVD
           graphene using Raman spectroscopy
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Rachid Fates, Hachemi Bouridah, Jean-Pierre Raskin In this study, we experimentally investigate the evolution of the Raman spectrum of single, bi- and tri-layer graphene as function of gate voltage induced doping. In single layer graphene, the observed results are in agreement with the literature. Whereas, for bi- and tri-layer graphene, we report new results on the gate voltage induced doping dependence of G and 2D bands position, the 2D to G band intensity ratio and the G band linewidth. The gate bias through 90 nm-thick oxide allows us to move the Fermi level up to 0.43 eV and 0.31 eV for bi- and tri-layer graphene, respectively. We observe one minima in the evolution of the G band position of bilayer as function of doping. This result is explained by the presence of a larger charge density non-uniformity, which yields to electron and hole puddles in the sample. The G band position and linewidth and the 2D to G band intensity ratio show a slow variation with doping near the neutrality point, this becomes more important as doping keeps rising such as the trends present a parabolic shape dependence. We assign this to the band structure of bi- and tri-layer graphene where the carriers are massive with respect to single layer graphene.Graphical abstractImage 1
       
  • Ultrasensitive Embedded Sensor for Composite Joints Based on a Highly
           Aligned Carbon Nanotube Web
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Sandeep Kumar, Brian G. Falzon, Stephen C. Hawkins Herein, we present a novel approach for damage sensing in adhesively bonded joints using a carbon nanotube single layer web (CNT-SLW) which marks a significant departure from the approach of dispersing CNTs within epoxy resins. In this work, a very thin, highly aligned CNT-SLW (densified thickness ∼ 50 nm) with aerial density of 2.0 μg/cm2 was horizontally drawn from a vertically aligned CNT forest, positioned over an adhesive film, which was, in turn, placed between two non-conductive composite adherents. This was followed by the application of heat and pressure to cure the adhesive. These joints were subjected to quasi-static and cyclic loading to investigate the damage sensing performance of a CNT-SLW. The CNT-SLW sensor, placed parallel to the load direction, exhibits remarkably high cyclic stability as well as exceptionally high sensitivity to damage initiation and accumulation. The resistance increase (ΔR/Ro% ∼1633%) is significantly higher than that of adhesive sensors with dispersed CNTs/graphene reported in the literature. Morphological studies help to explain the sensing mechanism through interactions of the CNT-SLW with the evolution of micro-cracks. These results demonstrate the potential of macroscopic architectures of CNTs, with controlled orientation, for the development of high performance structural health monitoring (SHM) systems for damage detection.Graphical abstractImage 1
       
  • Suppressing the Pd-C interaction through B-doping for highly efficient
           oxygen reduction
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Cai Zhang, Shansheng Yu, Yanan Xie, Wei Zhang, Kang Zheng, Nicholas E. Drewett, Seung Jo Yoo, Zizhun Wang, Lidong Shao, Hongwei Tian, Jin-Gyu Kim, Weitao Zheng As a potential alternative to commercial Pt/C, carbon supported Pd nanoparticles (NPs) is powerful in facilitating ORR. However, a strong interaction usually existing between Pd and carbon probably hinders the expression of ORR activity. This work focuses on tuning the interaction between Pd and graphene for architecting high-performance ORR catalyst. The strong interaction between Pd and graphene was confirmed, rendering significant microstructural variation, e.g., the dramatic change of lattice disorder and vibration of surface C-H/C-O bond for the graphene support. Boron (B)-doping enables reversing such structural evolution and suppressing the Pd-C interaction. It literates the Pd from the interaction, increases its electrochemical specific surface area (ECSA) from 68 to 125 m2 g−1 and thereof contributes to the highly efficient ORR performance in alkaline solution with more feasible 4e− pathway on a 2.8 wt% Pd/C catalyst. Moreover, theoretical simulations further proved that B-doping enhances the electron transfer between Pd and the graphene support and probably benefits a 4e− pathway for ORR.Graphical abstractImage 1
       
  • Ballistic transport in bent-shaped carbon nanotubes
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Zewen Wu, Yanxia Xing, Wei Ren, Yin Wang, Hong Guo We report theoretical investigations of ballistic quantum transport properties of smoothly bent semiconducting single-walled carbon nanotubes (SWCNTs). The SWCNT is doped into NxN and PxP forms where N and P stand for N-type and P-type doping, x takes N-type, P-type or intrinsic I-type. Our calculation is based on a state-of-the-art non-equilibrium Green's function approach combined with density functional theory. The smooth bent induces a small electron redistribution on the SWCNT arc, which leads to rich and major transport differences between the NxN and PxP tubes. Conductance G of NNN tubes does not change with the bending angle β, while G of PPP tubes decreases with it. G of NPN and PNP tubes increases with β, while that of the PNP tubes varies with it in an oscillatory manner. The bent induced transport phenomena can be well understood by analyzing the microscopic physics of the electronic density distribution and quantum interferences between scattering states which traverse different paths along the bent-shaped tubes. The predicted conductance versus bent angle is useful for estimating how a flexible system may behave when strained and/or bent.Graphical abstractImage 1
       
  • S+chemistry+by+porous+hollow+cobalt-B,+N+codoped-graphitic+carbon+polyhedrons+for+high+performance+lithium-sulfur+batteries&rft.title=Carbon&rft.issn=0008-6223&rft.date=&rft.volume=">Manipulating the redox kinetics of LiS chemistry by porous hollow
           cobalt-B, N codoped-graphitic carbon polyhedrons for high performance
           lithium-sulfur batteries
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Na Li, Kanghua Chen, Songyi Chen, Fei Wang, Dudan Wang, Fangyu Gan, Xuan He, Yuanchun Huang Lithium-sulfur batteries have attracted tremendous attention due to their inherently high theoretical energy density of sulfur cathode for next-generation energy storage systems. However, shuttle of soluble polysulfides and sluggish redox kinetics in sulfur cathode still limit its practical application. Herein, a hollow porous B,N-codoped graphitic carbon-Co composite (h-CoBN-GC) is synthesized, combining the advantages of synergetic structural and chemical bonding confinement to reserve the soluble polysulfides. A serial of further electrochemical redox kinetic studies confirm that the ultrafine Co nanoparticles and B, N-codoped species serve as dual electrocatalysts, substantially promote the redox of polysulfides reaction kinetics. Benefiting from the above merits, the as-obtained 80S@h-CoBN-GC composite demonstrates an improved electrochemical performance. It delivers a high first discharge capacity of 1089 mAh g−1 and remarkable capacity retention of 877 mAh g−1 after 500 cycles at 0.5C rate, with nearly 100% Coulombic efficiency maintenance. These results suggest that the 80S@h-CoBN-GC composite provides possibility of practical applications in high performance LiS batteries.Graphical abstractTo solve the two big problems (the shuttle effect of LiPSs and sluggish reaction kinetics), which hindered the commercialization of LiS batteries, a porous hollow cobalt-B, N codoped-graphitic carbon polyhedrons has been designed as a novel S host material for the first time to achieve excellent cycling stability and rate capability simultaneously. The h-CoBN-GC is consisted of homogeneously inlaid ultrafine Co nanoparticles in nitrogen-doped carbon shell. As a result of this fascinating structure, the h-CoBN-GC based sulfur cathode with 6.5 mg cm−2 sulfur delivers a high initial capacity of 520 mAh g−1 and remarkable capacity retention of 79% after 100 cycles at 0.5C.Image 1
       
  • Transferable ultra-thin multi-level micro-optics patterned by tunable
           photoreduction and photoablation for hybrid optics
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Hyub Lee, Mun Ji Low, Chin Huat Joel Lim, Jianing An, C.S. Suchand Sandeep, Thazhe Madam Rohith, Hyug-Gyo Rhee, Vadakke Matham Murukeshan, Young-Jin Kim Next-generation hybrid optics will provide superior performances over traditional optics by combining the advantages of refractive, reflective, and diffractive optics and metasurfaces. Hybrid optics have been realized by integrating diffractive optical structures to the top surface of traditional bulk refractive or reflective optics. However, high-resolution manufacturing requirement of diffractive patterns on top of free-form refractive or reflective optical surfaces have hindered the wide-spread dissemination of hybrid optics. In this paper, we demonstrate a transferable ultra-thin micro-optics having multi-level transmittance and phase profiles which are arbitrarily patterned by tunable photoreduction and photoablation of graphene oxides (GO) using femtosecond (fs) direct laser writing. A 5 × 5 array of multi-level ultra-thin micro diffractive lens having a focal length of 15 mm was exemplarily patterned with real-time laser power control; the resulting spot size was smaller than 14 μm with the suppression of diffractive side peaks by 14.9% at the first order and 10.8% at the second order ones. This laser-patterned diffractive lens array was successfully transferred to the surface of a refractive cylindrical lens via polydimethylsiloxane (PDMS) as the flexible/stretchable substrate; the resulting optical performance agrees well with the theoretical simulation result. This new fabrication method will pave a way to novel hybrid optical systems.Graphical abstractImage 1
       
  • A signal-on fluorescent sensor for ultra-trace detection of Hg2+ via Ag+
           mediated sulfhydryl functionalized carbon dots
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Yong Han, Limei Shi, Xueli Luo, Xiumei Chen, Weixia Yang, Wenzhi Tang, Jianlong Wang, Tianli Yue, Zhonghong Li Sulfhydryl functionalized carbon dots (HS-CDs) mediated by Ag+ were used to develop a fluorescent sensor for the determination of Hg2+ in aqueous solutions. FTIR and XPS confirmed the successful modification of -SH on the surface of HS-CDs. Dripping Ag+ into HS-CDs yielded brown agglomerates of silver thiolate leading to strong FL quenching of the HS-CDs. The signal-on fluorescent sensor was acheived by dispersing the precipitates in a PBS buffer (pH 7.4, 0.01 mol/L). Remarkable FL recovery was observed upon the addition of Hg2+ into the sensor owing to the energy trap induced by exposure of -NH2 on the surface of the HS-CDs. Fluorescence intensities of the HS-CDs were linearly recovered in Hg2+ concentrations of 0.01–0.75 nmol/L with an extremely low detection limit of 4.2 pmol/L. The sensor exhibited stronger specificity toward Hg2+ than co-existent metal ions. The detecting results for real water samples obtained by the sensor showed good agreement with ICP-AES (P > 0.05), demonstrating a sensitive and selective fluorescent nanosensor for ultra-trace determination of Hg2+ with acceptable precision and satisfactory accuracy.Graphical abstractImage 1
       
  • Ultrafast photonics application of graphdiyne in optical communication
           region
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Yang Zhao, Penglai Guo, Xiaohui Li, Zhiwen Jin As a kind of novel allotrope of carbon, graphdiyne (GDY) has attracted wide interest of scientists from different fields. Due to excellent electrical and optical properties, it has important and promising prospects in the fields of energy, catalysis and optoelectronics, etc. However, investigations of this emerging material on nonlinear optics and ultrafast photonics are rarely involved. In our work, we have fabricated a saturable absorber (SA) based on graphdiyne and applied it to an erbium-doped fiber laser at the 1.5 μm region. Based on the evanescent field interaction, we obtain the mode-locked laser pulse at a center wavelength of 1564.70 nm which has a repetition rate of 12.05 MHz and a pulse width of 734 fs. This is the first time that graphdiyne has been used as a SA to obtain a mode-locked fiber laser in femtosecond level, which proves the great prospect of graphdiyne on fiber lasers and opens up a path for its application in ultrafast photonics and optoelectronics.Graphical abstractImage 1
       
  • Spatial dependence of the growth of polycyclic aromatic compounds in an
           ethylene counterflow flame
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Qi Wang, Paolo Elvati, Doohyun Kim, K. Olof Johansson, Paul E. Schrader, Hope A. Michelsen, Angela Violi The complex environments that characterize combustion systems can influence the distribution of gas-phase species, the relative importance of various growth mechanisms and the chemical and physical characteristics of the soot precursors generated. In order to provide molecular insights on the effect of combustion environments on the formation of gas-phase species, in this paper, we study the temporal and spatial dependence of soot precursors growth mechanisms in an ethylene/oxygen/argon counterflow diffusion flame. As computational tools of investigation, we included fluid dynamics simulations and stochastic discrete modeling. Results show the relative importance of various reaction pathways in flame, with the hydrogen-abstraction-acetylene-addition mechanism contributing to the formation of pure hydrocarbons near the stagnation plane, and oxygen chemistry prevailing near the maximum temperature region, where the concentration of atomic oxygen reaches its peak and phenols, ethers and furan-embedded species are formed. The computational results show excellent agreement with measurements obtained using aerosol mass spectrometry coupled with vacuum-ultraviolet photoionization. Knowledge acquired in this study can be used to predict the type of compounds formed in various locations of the flame and eventually provide insights on the environmental parameters that influence the growth of soot precursors. Additionally, the results reported in this paper highlight the importance of modeling counterflow flames in two or three dimensions to capture the spatial dependence of growth mechanisms of soot precursors.Graphical abstractImage 1
       
  • Diamond-like carbon structure-doped carbon dots: A new class of
           self-quenching-resistant solid-state fluorescence materials toward
           light-emitting diode
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Huiyu Li, Zhaoxuan Zhang, Jie Ding, Yang Xu, Guangrui Chen, Jiale Liu, Li Zhao, Ning Huang, Zhongyu He, Yi Li, Lan Ding The construction of simple and low-cost light-emitting diode (LED) based on carbon dots (CDs) powder is an important and challenging task. Here, diamond-like carbon (sp3C) structure-doped carbon dots (D-CDs) powder was prepared within 8 min via a one-step microwave-assisted pyrolysis route with a high production yield of 67.8%. The obtained D-CDs powder emits bright solid-state fluorescence without any other additional solid matrices and exhibits a quantum yield of 67.7%. Self-quenching effect caused by direct π-π interactions and fluorescence resonance energy transfer is strongly suppressed by the sp3 and sp2 carbon hybrid structure and the single energy level in the D-CDs powder. The D-CDs powder was directly employed as phosphors in LED, and bright blue LED was successfully constructed with maximum luminance achieving 3922 cd m−2. More importantly, the introduction of diamond-like carbon (sp3C) structure opens a new era for the preparation of CDs powder with solid-state fluorescence.Graphical abstractImage 1
       
  • Magic auxeticity angle of graphene
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Jie Hou, Binghui Deng, Hanxing Zhu, Yucheng Lan, Yunfeng Shi, Suvranu De, Li Liu, Pritam Chakraborty, Fei Gao, Qing Peng Solids exhibit transverse shrinkage when they are stretched, except auxetics that abnormally demonstrate lateral expansion instead. Graphene possesses the unique normal-auxeticity (NA) transition when it is stretched along the armchair direction but not along the zigzag direction. Here we report on the anisotropic temperature-dependent NA transitions in strained graphene using molecular dynamics simulations. The critical strain where the NA transition occurs increases with respect to an increase in the tilt angle deviating from armchair direction upon uniaxial loading. The magic angle for the NA transition is 10.9°, beyond which the critical strain is close to fracture strain. In addition, the critical strain decreases with an increasing temperature when the tilt angle is smaller than the NA magic angle. Our results shed lights on the unprecedented nonlinear dimensional response of graphene to the large mechanical loading at various temperatures.Graphical abstractImage 1
       
  • Systematic investigation of the catalyst composition effects on
           single-walled carbon nanotubes synthesis in floating-catalyst CVD
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Saeed Ahmad, Yongping Liao, Aqeel Hussain, Qiang Zhang, Er-Xiong Ding, Hua Jiang, Esko I. Kauppinen Enormous technological promise of single-walled carbon nanotubes (SWCNTs) can only be harnessed with the premise of controllable synthesis of SWCNTs, where catalyst composition thermodynamically plays a vital role. Herein, we have systematically investigated the effects of catalyst composition on SWCNTs synthesis, using a novel floating-catalyst chemical vapor deposition (FCCVD) system, consisting of catalyst synthesis via spark generator, FCCVD reactor and a real-time monitor of catalysts and SWCNTs. We synthesized SWCNTs from both monometallic (Fe, Co, Ni), bimetallic (Co-Ni, Co-Fe) catalyst particles and kinetically optimized yield and performance of SWCNTs films. We found that the highest yield of SWCNTs from Fe is 15 times as that of Ni SWCNTs and the Co-Ni SWCNTs film possesses best opto-electronic performance. Interestingly, the mean diameter of SWCNTs was found related to the catalyst particle size distributions, but not composition. Moreover, detailed atomic structures determination revealed that SWCNTs from Fe and Co have a wide chirality distribution spanning from zig-zag to armchair edges. However, Co-Ni SWCNTs have comparatively narrower chirality distribution having 71% SWCNTs in the chiral angle of 15–30°. Our results indicate that catalyst composition can efficiently tune yield and characteristics of SWCNTs, but it does not dramatically shift chirality of FCCVD SWCNTs.Graphical abstractImage 1
       
  • Early oxidation stages of germanium substrate in the graphene/Ge(001)
           system
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): P. Dabrowski, M. Rogala, I. Pasternak, P. Krukowski, J.M. Baranowski, W. Strupinski, I. Lutsyk, D.A. Kowalczyk, S. Pawłowski, Z. Klusek Kelvin Probe Force Microscopy (KPFM) in combination with Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy/Spectroscopy (STM/STS), and X-ray Photoelectron Spectroscopy (XPS) were used to study early stages of oxidation of germanium in the graphene/Ge(001) system exposed to atmospheric environment. KPFM measurements allowed to distinguish nanoscale regions, which are not covered by graphene, as a result of graphene domain misorientation in the growth process. In this area, corrosion process penetrated the region underneath graphene, which can be observed at the nano- and microscale. Therefore, the electronic properties of graphene/germanium hybrid system are modified in the regions around defects. Whereas graphene can protect surfaces against oxidation, the described processes have impact of electronic properties of the sample in a long time scale. We showed that early oxidation stages can be identified in nanoscale even when macroscopic techniques such as XPS do not show signs of degradation. The obtained results are important for assessing the need of protection of graphene/Ge(001) devices.Graphical abstractImage 1
       
  • Functionalized carbon nanotubes as phase change materials with enhanced
           thermal, electrical conductivity, light-to-thermal, and electro-to-thermal
           performances
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Ruirui Cao, Sai Chen, Yuzhou Wang, Na Han, Haihui Liu, Xingxiang Zhang Light- and electro-driven hexadecyl acrylate-functionalized single/multi-wall carbon nanotubes (HDA-g-SWCNT, HDA-g-MWCNT) solid-solid phase change materials (SSPCMs) were fabricated via a green Diels-Alder reaction. Both HDA-g-SWCNT and HDA-g-MWCNT show enhanced thermal and electrical conductivities, appropriate phase change temperature, almost no supercooling degree and effective phase change enthalpy. HDA was covalently grafted onto the surface of SWCNT/MWCNT. The phase transition enthalpy (ΔHh) and phase transition temperature (Thp) in the heating process, crystallization enthalpy (ΔHc) and crystallization temperature (Tcp) in the cooling process of HDA-g-SWCNT are 52 J/g, 36.7 °C, 51 J/g, and 23.7 °C, respectively. The ΔHh, Thp, ΔHc, and Tcp of HDA-g-SWCNT are 40 J/g, 38.0 °C, 39 J/g, and 26.8 °C, respectively. The HDA-g-SWCNT/HDA-g-MWCNT can effectively convert electric or light energy into thermal energy under electric field or solar illumination. Meanwhile, the electrical conductivity of HDA-g-SWCNT and HDA-g-MWCNT films reached up to 718 and 389 S/m, respectively. The phase change property and enhanced thermal conductivity of HDA-g-SWCNT and HDA-g-MWCNT enable them to be used as a heat spreader for electronic cooling applications. Furthermore, the HDA-g-SWCNT and HDA-g-MWCNT exhibited good thermal stability, great thermal reliability, and shape stability, potentially leading to new energy systems with multi-responsive performance for electronic devices, solar energy utilization, and thermal management.Graphical abstractImage 1
       
  • Holey graphenes as the conductive additives for LiFePO4 batteries with an
           excellent rate performance
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Lingtao Xu, Wei Lv, Kai Shi, Shujie Xiao, Conghui You, Yan-Bing He, Feiyu Kang, Quan-Hong Yang Graphene has been investigated and widely used as the high performance conductive additives in lithium ion batteries. Unfortunately, the LiFePO4 batteries with graphene additives present quite a low rate performance because the graphene with planar structure blocks the Li ion transportation. Herein, a binary conductive additive containing only 1 wt% holey graphene (HG) and 1 wt% Carbon Black such as Super-P (SP) has been developed, which achieves excellent high-rate performance for the LiFePO4 battery that is comparable to that of the battery with 10 wt% SP. The HG with large amount of holes and large specific surface area substantially enhances the electronic conductivity of LiFePO4 electrode, but not compromises the high efficient ionic transportation. A small content of SP as the supplement of long-range conductive network formed by HG can contact the LiFePO4 sufficiently for achieving excellent conductivity in the whole LiFePO4 electrode. A balance of electronic conductivity and ionic diffusivity can be achieved using the HG and SP simultaneously. The HG and SP with low content can synergistically construct an excellent ionic and electronic conductive network in LiFePO4 electrode. This study may promote the commercial applications of HG additives for high performance LiFePO4 batteries.Graphical abstractImage 1
       
  • Smart carbon foams with switchable wettability for fast oil recovery
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Yuheng Xu, Zedong Zhang, Xiangfei Geng, Jing Jin, Muzaffar Iqbal, Aijuan Han, Bin Ding, Junfeng Liu The adsorption and recovery of crude-oil from oily water using oil-selective adsorbents is a highly promising solution for the increasing worldwide oil pollution, but remain a challenge. Herein, we reported a carbon foam (CF) with switchable wettability as smart materials for fast oil adsorption and recovery. By grafting poly(4-vinylpyridine) (P4VP) onto the surface of CF, the obtained smart foam presented a pH responsiveness and could change superhydrophilic and superhydrophobic surface according to the pH value. Thus, the smart responsive carbon foam could fast adsorb the oil in neutral solution (pH = 7) with high oil adsorption capacity of 62–120 g g−1 and desorb all the adsorbed oil in acidic solution (pH = 1) within 1.5 min. In addition, only 3% loss was observed for oil (chloroform) adsorption and recovery after successive reuses of up to 15 cycles, which demonstrated great recyclability of the materials.Graphical abstractA pH-responsive 3D porous carbon foam is rationally designed for the highly effective adsorption and fast recovery of oil from aqueous media. With the switchable surface wettability between superhydrophilicity and superhydrophobicity according to pH values, the 3D porous carbon foam can adsorb and release oil in neutral and acidic solution, respectively, demonstrating great ability for oil adsorption and recovery.Image 1
       
  • Two-dimensional graphyne-like carbon nitrides: Moderate band gaps, high
           carrier mobility, high flexibility and type-II band alignment
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Siyun Qi, Xikui Ma, Bo Yang, Lei Sun, Weifeng Li, Mingwen Zhao Two-dimensional (2D) carbon nitrides are drawing increasing interests due to the structural diversities and unique electronic properties, superiors to the pure 2D carbon materials. Motivated by the recent experimental progresses, we investigated from first-principles a new family of 2D carbon nitrides composed of sp- and sp2-hybridized carbon atoms and with kagome, rhombic and hexagonal lattices. The kagome and rhombic lattices exhibit moderate electronic band gaps (0.98–3.34 eV), high carrier mobility in the order of 3 × 105 cm2V−1s−1, high flexibility with critical strain up to 44%–47%, and type-II band alignment which are desired for applications in electronic devices and solar cells. Our findings are expected to offer theoretical bases for synthesis and applications of these novel 2D carbon nitrides and promote the following experimental exploration.Graphical abstractImage 1
       
  • The experimental and theoretical insights towards the CO induced
           Pd-Graphene and their multifunctional energy conversion applications
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Sushanta K. Das, Subash Chandra Sahu, Arnab Ghosh, Suddhasatwa Basu, Brahmananda Chakraborty, Bikash Kumar Jena Here, CO gas environment has been used for reduction of graphene oxide (GO) and Pd precursor for preparation of varieties of Pd Nanostructures (PdNSs) with different shapes, size and surface morphologies on graphene support (RG-PdNSs). The extensive ab-initio Molecular Dynamics (MD) simulations and electronic structure calculations have been carried to get theoretical insight for the reduction process of GO by CO. The reduction of GO by CO as observed in experiment are confirmed by ab-initio MD snapshots at different time steps, energetic of the process and the Partial Density of States character of O2p orbital of GO before and after interaction with CO. The discrete states in the Partial Density of States of O2p orbital after CO attack indicates detachment of O from GO. The as-prepared RG-PdNSs are thoroughly characterized by different techniques. The simulation reveals the change in electronic properties from semi-metallic in pristine graphene to metallic due to the attachment of Pd in RG-PdNSs. The electrocatalytic activity of the as-synthesized nanostructures has been investigated toward the multi-functional energy conversion applications, the methanol oxidation reaction, formic acid oxidation reaction and oxygen reduction reaction. The RG-PdNSs exhibit excellent electrocatalytic performance compared to that of unsupported PdNSs and commercial Pd/C.Graphical abstractImage 1
       
  • Bio-molecule adenine building block effectively enhances electromagnetic
           interference shielding performance of polyimide-derived carbon foam
    • Abstract: Publication date: August 2019Source: Carbon, Volume 149Author(s): Chengfeng Li, Chuxiang Zhou, Jiangbo Lv, Bo Liang, Renke Li, Yao Liu, Jianghuai Hu, Ke Zeng, Gang Yang Heteroatom doping porous carbon material possess a variety of attractive functionality such as electrical properties, catalytic properties and adsorptive capability. As an important building block of DNA, adenine has following characteristics: 1. Heterocyclic structure 2. Potential interaction modes 3. Flexible structure tailor ability 4. Available from biomass. In this study, adenine-containing polyimide (API) foam has been prepared by freeze-drying, and is used as polymer precursor of nitrogen doping carbon foam (ACF). The carbon foam (PCF) prepared by adenine-free PI foam (PMDA ODA PI) is used as a comparison. The results show that the nitrogen content of ACF after carbonization at 1000 °C (ACF-1000) is as high as 4.35%, which is about twice higher than PCF-1000 (1.90%). The conductivity of ACF-1000 is 7.11 × 10−1 s cm−1, which is 38.06% larger than PCF-1000 (5.15 × 10−1 s cm−1). The electromagnetic interference shielding effectiveness (EMI SE) of ACF-1000 is 41.1 dB, which is 26.85% higher than PCF-1000 (32.4 dB). The SSE/d (defined as the SE divided by the thickness and density of the shielding material) of ACF-1000 is 13569 dB cm2/g, which is 66.41% higher than PCF-1000 (8154 dB cm2/g). This work shows that adenine is a promising nitrogen-doping building block for polymer-derived carbon materials. The introduction of adenine structure into the polymer is helpful for improving the EMI shielding performance of carbonized products.Graphical abstractAdenine building block can effectively enhance electrical conductivity (7.11 × 10−1 s cm−1), and electromagnetic interference shielding performance (∼41.1 dB and 13569 dB cm2/g at 13 mm thickness) of polymer-derived carbon foam.Image 1
       
  • Hierarchical nickel-cobalt phosphide hollow spheres embedded in P-doped
           reduced graphene oxide towards superior electrochemistry activity
    • Abstract: Publication date: Available online 17 April 2019Source: CarbonAuthor(s): Tao Dong, Xiao Zhang, Peng Wang, Hsueh-Shih Chen, Ping Yang Hierarchical bimetallic Ni-Co phosphides hollow spheres were encapsulated in P-doped reduced graphene oxide (PrGO) to provide superior electrochemistry performances. The hollow spheres with controlling Co/Ni ratios were obtained via a hydrothermal process and following phosphorization reaction using Ni-Co based glycerate microsphere as a self-sacrificing template. The hollow shell with vertical branches was formed via a morphology evolution of solid, yolk-shell to hollow. The hollow spheres were encapsulated in PrGO networks by a hydrothermal synthesis and phosphorization process to fabricate PrGO/Ni-Co phosphide composite (PrGO/NiCoP). Because of unique morphology and composition, the composite with a Ni/Co molar ratio of 1:1 exhibits enhanced supercapacitor and electrocatalysis properties. As a supercapacitor electrode, PrGO/NiCoP provides high discharge specific capacity, excellent rate performance and cycle stability. An asymmetric supercapacitor assembled with PrGO/NiCoP and activated carbon possesses an energy density of 49.7 Wh/Kg with power density of 0.366 kW/kg, which can successfully illuminate red-light light emitting diode. As an electrocatalyst, PrGO/NiCoP exhibits high hydrogen and oxygen evolution reaction activities in 1 M KOH electrolyte. PrGO/NiCoP electrolyzer shows excellent overall water splitting performance and durability, which required a cell voltage of 1.56 V to achieve a current density of 10 mA cm−2.Graphical abstractNiCoP hollow microsphere/phosphorus-doped reduced graphene oxide composites have been successfully synthesized, which exhibits superior asymmetric supercapacitor and electrocatalytic overall water splitting performances.Image 1
       
  • Graphene oxide as antibacterial sensitizer: Mechanically disturbed cell
           membrane for enhanced poration efficiency of melittin
    • Abstract: Publication date: Available online 17 April 2019Source: CarbonAuthor(s): Shufeng Xiao, Xuemei Lu, Lu Gou, Jingliang Li, Yuqiang Ma, Jiaojiao Liu, Kai Yang, Bing Yuan Natural antimicrobial peptides (AMPs) promise a fundamental solution to the devastating threat of multidrug-resistant bacteria, while drawbacks such as limited antibacterial efficiency block their clinical use. A key for solution is to enhance the bacterial membrane disruption ability of AMPs at low concentrations. Here, it was found that a small amount of graphene oxide (GO) nanosheets could have a strong effect on sensitizing lipid membranes to the peptide melittin and extremely decrease the required threshold concentration of melittin for killing of bacteria. Molecular leakage tests from model vesicles showed that pretreatment of membrane with GO, even at a low concentration of 0.1 μg mL−1, decreased the threshold working concentration of melittin to less than half of the initial value, while in the living bacteria tests, such sensitizing effect of GO reduced the MIC value of melittin by almost 10 times. By combining experiments and simulations, we found that the sensitizing effect of GO was derived from its similar mechanical disturbance to cell membranes as that of melittin at high concentrations in membrane structures including lipid diffusion, packing state, and pressure distribution. Our results provide a cost-effective strategy to enhance the antibacterial efficiency of AMPs for clinical use.Graphical abstractImage 1
       
  • High-energy quasi-solid-state supercapacitors enabled by carbon nanofoam
           from biowaste and high-voltage inorganic gel electrolyte
    • Abstract: Publication date: Available online 16 April 2019Source: CarbonAuthor(s): Zhiwei Li, Song Gao, Hongyu Mi, Chenchen Lei, Chenchen Ji, Zongli Xie, Chang Yu, Jieshan Qiu Focusing on major issues of carbon materials like insufficient capacitance and limited energy supply in supercapacitors, we propose the strategy of developing advanced carbon and high-voltage inorganic gel electrolyte to efficiently solve these challenges. Firstly, the architecture of self-doped carbon nanofoam (A-CS650) is fabricated utilizing naturally rich cotton stalk through a facile procedure, which demonstrates exceptional performance contributed by synergistic features of large surface area, hierarchical porosity and rich defects. A-CS650 presents gravimetric and volumetric capacitances up to 282 F g−1 and 234 F cm−3 at 0.5 A g−1, and a high-rate capacitance retention of 72.7% at a large rate of 100 A g−1. With increasing the mass loading to 20 mg cm−2, A-CS650 still retains good performance. Especially, by using unique CMC-Na/Na2SO4 gel electrolyte, 1.8 V A-CS650//A-CS650 quasi-solid-state supercapacitor, for the first time, is constructed, which displays an outstanding energy density of 22.6 Wh kg−1, greatly exceeding the value in PVA/KOH electrolyte (7.3 Wh kg−1). Besides, this device exhibits considerable stability over 10000 cycles (81.6% capacitance retention). This insight from this work verifies great adaptability of biowaste-derived carbons toward supercapacitors, and may open a new technical platform to develop portable energy systems.Graphical abstractImage 1
       
  • High cross-plane thermally conductive hierarchical composite using
           graphene-coated vertically aligned carbon nanotubes/graphite
    • Abstract: Publication date: Available online 15 April 2019Source: CarbonAuthor(s): Feng Lv, Mengmeng Qin, Fei Zhang, Huitao Yu, Long Gao, Peng Lv, Wei Wei, Yiyu Feng, Wei Feng Thermally conductive carbon-based composites in the cross-plane direction is of significant importance for efficient heat dissipation. Fabricating one-dimensional (1D) ordered structure at the interlayer of graphite (GT) effectively improves its cross-plane thermal conductivity (k⊥). However, this structure deteriorates during subsequent hot-pressing owing to its low structural stability. Herein we report a three-dimensional (3D) graphene-coated vertically aligned carbon nanotubes (VACNTs)/graphite (GT) composite with high k⊥ value. A uniform coating of reduced graphene oxide (rGO) on VANCTs results in efficient heat conduction throughout the large-area, bendable nanosheets and forms ordered arrays in the cross-plane direction owing to the high structural integrity. The thermal conductivity of the graphite-based blocks prepared by hot-pressing can be controlled via combined effects of the length of the VACNTs used for the two-dimensional (2D) coating and uniformity of the rGO coating. With a relatively low density (1.67 g/cm3), the rGO-VACNTs/GT composite exhibits a maximum k⊥ value of 32.96 W/m·K, 60% higher than VACNTs/GT (20.1 W/m·K; density = 1.85 g/cm3). Laser-induced thermochromic patterns confirm that the rGO-VACNTs/GT composite exhibits excellent heat conduction. Thus, 2D-coated/1D array assemblies can be developed for advanced high-strength and thermally-conductive materials by optimizing their hierarchical microstructure.Graphical abstractImage 1
       
  • Mechanism studies and fabrication for the incorporation of carbon into Al
           alloys by the electro-charging assisted process
    • Abstract: Publication date: Available online 15 April 2019Source: CarbonAuthor(s): X. Ge, C. Klingshirn, M. Wuttig, K. Gaskell, P.Y. Zavalij, Y. Liang, C.M. Shumeyko, D.P. Cole, L.G. Salamanca-Riba The incorporation of carbon nanostructures into Al alloys has the potential to further improve the mechanical and electrical properties of these alloys. We report a novel one-step fabrication method of incorporating carbon in aluminum alloys by the application of a high electric current to molten Al metal containing particles of activated carbon at high temperature and under Ar atmosphere. We propose that the mechanism for carbon incorporation is similar to electromigration where the current facilitates ionization of the carbon atoms followed by polymerization of the carbon structures and the formation of graphitic chains and ribbons along preferred directions of the Al lattice. Furthermore, the current induces transformation from amorphous carbon to crystalline graphitic structures that propagate in the metal matrix. The carbon is identified by the C-K edge in electron energy loss spectra, X-ray photoelectron spectroscopy, Raman and Kelvin probe force microscopy. The stiffness is increased in these samples; hardness, on the other hand, decreases for some samples compared to reference Al alloys with no carbon. The electrical conductivity is superior to that of Al-carbon nanotube composites previously reported. The enhanced properties of Al covetics show potential for naval and aerospace applications and power transmission lines.Graphical abstractImage 1
       
  • Water-based and inkjet printable inks made by electrochemically exfoliated
           graphene
    • Abstract: Publication date: Available online 15 April 2019Source: CarbonAuthor(s): Khaled Parvez, Robyn Worsley, Adriana Alieva, Alexandre Felten, Cinzia Casiraghi Inkjet printable graphene inks are very attractive for applications in flexible and foldable electronics, such as wearable electronics and the Internet of Things. However, the ink preparation is still very time consuming as high concentrations can be achieved only with prolonged sonication (>24 h) or with expensive setups. Here we demonstrate a water-based inkjet printable ink made from electrochemically exfoliated graphene. A printable and stable (>1 month) ink with concentration of ∼2.25 mg mL−1 was formulated in less than 5 h, using two successive steps: first exfoliation and dispersion of large graphene flakes (>5 μm) followed by 1 h tip-sonication to reduce the flake size below 1 μm, as required for the material to be able to be ejected by the nozzle. The formulated ink contains more than 75% single- and few-layers (i.e. less than 2 nm in thickness) graphene flakes with an average lateral size of 740 nm. Thermal annealing allows to achieve high C/O ratio (>10), which translates into one of the highest electrical conductivity (≈3.91 × 104 S m−1) reported so far for solution-processed graphene, without the use of any harsh chemical processing.Graphical abstractImage 1
       
  • Structuration of lignin-graphene oxide based carbon materials through
           liquid crystallinity
    • Abstract: Publication date: Available online 14 April 2019Source: CarbonAuthor(s): Marie Föllmer, Simon Jestin, Wilfrid Neri, Alain Derré, Ahmed Bentaleb, Célia Mercader, Philippe Poulin This paper presents the approach of combining lignin with graphene oxide (GO) flakes in order to introduce a higher structuration inside amorphous carbon materials. Both the phase behavior of lignin-GO solutions and the properties of lignin-GO films are investigated in a first approach. A clear orientation within lignin-based solutions is obtained through the formation of a nematic liquid crystalline GO phase. The impact of the GO flakes on the lignin-GO films after their carbonization is demonstrated via scanning electron microscopy and X-ray diffraction measurements. With increasing GO content inside the composite films, a layer-like morphology and graphitic structures of higher crystallinity are found. The electrical conductivity of the films gradually increases as well. Furthermore, we demonstrate successful spinning trials of lignin-GO solutions into composite fibers by means of coagulation. An increased electrical conductivity of the obtained fibers depending on the GO concentration indicates an increase in crystallinity. The structuration of lignin-based carbon materials may represent an important approach towards bio-based carbon fibers with improved mechanical and electrical properties.Graphical abstractImage 1
       
  • Highly conductive and stretchable conductors integrated with sandwich
           graphene-carbon nanotube hybrid and styrene-butadiene rubber
    • Abstract: Publication date: Available online 12 April 2019Source: CarbonAuthor(s): Zijin Liu, Zhenghua Qian, Jianan Song, Yong Zhang A simple and effective approach, i.e., an emulsion blending followed by freeze-drying process, was developed to construct an electrically conductive and stretchable reduced graphene oxide (rGO)-carbon nanotube (CNT) network in styrene-butadiene rubber (SBR) composites. The rGO-CNT hybrids with sandwich structure were prepared by one-step hydrothermal process. One-dimensional carbon nanotubes, acted as spacers, were inserted between two-dimensional rGO sheets, which could effectively prevent the restacking of graphene sheets and the agglomeration of carbon nanotubes. Besides, carbon nanotubes connected with rGO sheets as bridges, facilitating the construction of a one-and two-dimensional interconnected network in SBR composites. The electrical conductivity of SBR/rGO-CNT (100/10.4) composite was 3.62 S/cm, which was significantly enhanced by 14 orders of magnitude as compared with that of SBR. Interestingly, the SBR/rGO-CNT composites could maintain their high electrical conductivity under low tensile strain. The high electrical conductivity and stretchable performance of the SBR composites were attributed to the one-and two-dimensional interconnected network, which was constructed via carbon nanotubes connecting rGO sheets and could be deformed under low strain. This work provides a new insight into the fabrication of stretchable composites with high electrical conductivity for versatile and practical applications.Graphical abstractImage 1
       
 
 
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