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CHEMISTRY (632 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: 28)
ACS Catalysis     Hybrid Journal   (Followers: 46)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 22)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 27)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 42)
ACS Nano     Hybrid Journal   (Followers: 308)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription  
ACS Synthetic Biology     Hybrid Journal   (Followers: 25)
Acta Chemica Iasi     Open Access   (Followers: 5)
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: 3)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 6)
Advanced Functional Materials     Hybrid Journal   (Followers: 60)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 75)
Advances in Chemical Science     Open Access   (Followers: 19)
Advances in Chemistry     Open Access   (Followers: 24)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19)
Advances in Drug Research     Full-text available via subscription   (Followers: 25)
Advances in Environmental Chemistry     Open Access   (Followers: 7)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
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: 15)
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: 3)
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: 68)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 22)
American Journal of Chemistry     Open Access   (Followers: 32)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 16)
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: 181)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 259)
Annales UMCS, 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: 13)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 25)
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: 3)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 378)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
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: 23)
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: 139)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 90)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
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: 24)
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: 11)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 25)
Carbon     Hybrid Journal   (Followers: 71)
Catalysis for Sustainable Energy     Open Access   (Followers: 8)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 12)
Cellulose     Hybrid Journal   (Followers: 10)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 21)
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: 27)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 205)
Chemical Science     Open Access   (Followers: 28)
Chemical Technology     Open Access   (Followers: 34)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 23)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 33)
Chemistry & Industry     Hybrid Journal   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 168)
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: 45)
Chemistry of Materials     Hybrid Journal   (Followers: 268)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 20)
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: 2)
Chromatography Research International     Open Access   (Followers: 6)
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: 22)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 7)
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: 12)
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: 1)
Current Metabolomics     Hybrid Journal   (Followers: 5)
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: 73)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 2)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 4)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)

        1 2 3 4 | Last

Journal Cover
Journal Prestige (SJR): 2.226
Citation Impact (citeScore): 7
Number of Followers: 71  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0008-6223
Published by Elsevier Homepage  [3157 journals]
  • Role of oxygen functional groups for improved performance of
           graphene-silicone composites as a thermal interface material
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Seul-Yi Lee, Prashant Singh, Roop L. Mahajan We report the findings of our experimental investigation on the performance of reduced graphene oxide (rGO)/silicone composite as a thermal interface material (TIM) influenced by the loading factor, surface functionality, and structural properties of graphene. The experimental data reveals that in addition to the loading factor, the thermal conductance of TIMs is greatly impacted by the density of oxygen-functionality (phenolic group) in rGO, and the morphological and structural properties introduced during the thermal reduction (deoxygenation) of graphene oxide to rGO. In particular, the phenolic groups prominently formed on the basal plane of rGO play a significant role in decreasing the interfacial thermal resistance. The results also show that the larger sp2 graphitic structures and the morphological properties of rGO increase the degree of dispersion in the matrix. A dynamic interplay between these factors determines the final value of the thermal conductance observed for different composites. An optimum combination of these factors led to the maximum thermal conductance (541 W/m2K) for the T-rGO600 (thermally-reduced graphene oxide processed at 600 °C)/silicone composite. The proposed underlying physics backed by the experimental data should be useful in designing high thermal performance TIMs with carbonaceous nanomaterials, including carbon nanotubes, graphene nanoplatelets, and carbon blacks acting as additives.Graphical abstractImage 1
  • Effects of carbon nanotube thermal conductivity on optoacoustic transducer
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Jiapu Li, Xuekai Lan, Shuang Lei, Jun Ou-Yang, Xiaofei Yang, Benpeng Zhu CNT-PDMS composite is regarded as a promising candidate for optoacoustic transducer application. However, the relationship between the CNT thermal conductivity and optoacoustic transducer performance is still undefined. To explore this relationship, four types of CNTs with different diameters and lengths were employed to successfully fabricate four types of optoacoustic transducers. The thermal properties of CNTs were analyzed and discussed in this paper; the laser-generated ultrasound and optoacoustic conversion efficiency of the transducers were experimentally and theoretically investigated. Results of comparison revealed the CNT with a diameter and length of 8 nm and 10–30 μm, respectively, to have the highest thermal conductivity. With this type of CNT/PDMS composite, the optoacoustic conversion efficiency reached as high as 9.59 × 10−3. Overall, the results demonstrate that higher CNT thermal conductivity corresponds to better optoacoustic transducer performance.Graphical abstractImage 1
  • Rational design of porous carbon matrices to enable efficient lithiated
           silicon sulfur full cell
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Usman Zubair, Julia Amici, Sandra Martinez Crespiera, Carlotta Francia, Silvia Bodoardo Lithium sulfur technology is a promising near-future battery owing to its high theoretical capacity and low cost materials; nonetheless, its commercial viability is hindered owing to the use of lithium anode. Reactive Li is prone to dendritic growth, causing short-circuits and aggravating electrolyte depletion. Here, lithiated silicon sulfur (SLS) full cells are realized by opting all-designs integrated strategy to rationally architecture the carbon matrices for both electrodes. For cathode, N/S- doped high surface area hierarchical porous carbons are designed to host sulfur and its redox species. Anodes are constructed by electrospinning using nano-silicon@void@carbon nanofibers (SVCNF) cross-linked with alginate-citric acid binder network. As-prepared anodes are reversibly alloyed and dealloyed with high reversible capacity of 2132 mAh gSi−1 (427 mAh gSi/CNF−1) after 150 cycles at 716 mA gSi−1 in ether-based electrolyte. At cathode, polypyrrole activated hierarchical carbon sulfur (PPyr_C/S) exhibits very stable performance with capacity retention around 767 mAh gS−1 after 250 at C/5. After balancing with low Li excess, lithiated SVCNF anodes are coupled with PPyr_C/S cathodes, with initial capacity of 972 mAh gS−1 and 50% capacity retention after 100 cycles at 225 mA gS−1. Full SLS cells have been appreciated by opting rational architecture of carbon matrices in individual electrodes even at low lithium excess.Graphical abstractImage 1
  • Precisely controllable hybrid graphene scaffold reveals size effects on
           differentiation of neural progenitor cells in mimicking neural network
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Xun Ma, Miao Xiao, Ying Hao, Guosheng Cheng Well-connected neural network in three-dimensional (3D) scaffolds is essential to replicate the neural connections in vivo. The large spacing size in scaffolds enabling cellular entrance through the pores and sufficient neurites across large spacings addresses a “catch-22” problem. Here, this study presents a conductive, interconnected and free-standing 3D hybrid graphene (3D-HG) scaffold with excellent biocompatibility and precise structural controllability. The unique design of two-dimensional graphene film in 3D-HG facilitated the differentiated neural progenitor cells (NPCs) to bridge the spacings between skeletons and promoted the formation of neural networks. Furthermore, skeleton sizes in 3D graphene scaffold have significant impact on the differentiation behaviors of NPCs. This strategy would favor the simulation of neural tissues and expand the use of graphene in neural tissue engineering, providing a powerful tool to explore the physical effects on cell behaviors.Graphical abstractA conductive, penetrable, integrated 3D hybrid graphene with excellent biocompatibility and admirable structural controllability facilitated neural progenitor cells (NPCs) to bridge the large spacings and promoted the NPCs differentiation into neural network. Size effects in 3D graphene scaffold have evident impact on the differentiation behaviors of NPCs.Image 1
  • Impact of natural and synthetic graphite milling energy on lithium-ion
           electrode capacity and cycle life
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Maciej Ratynski, Bartosz Hamankiewicz, Michal Krajewski, Maciej Boczar, Dominika Ziolkowska, Andrzej Czerwinski The article presents a correlation between a graphite milling energy and electrochemical performance of the Li-ion graphite electrode. Synthetic and natural graphite electrodes were examined and six different milling energy values were applied to each graphite type. For the first time, ethanol was successfully used as a liquid milling media. Results indicate a clear relationship between a milling energy, an initial capacity, and a cycle life behavior of the electrode. The high capacity and cycling stability were attributed to the ethanol presence during milling since it modified the active material surface by a partial oxidation. The ethanol-induced oxidation during a milling process promotes a more stable SEI layer formation. According to this research, we can design a simple milling process for the best graphite intercalation capacity in Li-ion cells. Energy calculations allow for an easy transfer of this technology between laboratories or large-scale commercial manufactures. To the best of our knowledge, those are the first milled graphite electrode examinations that include a high charge/discharge rate with 100 full cycles. This is also the first time that the ethanol wet-milling process is used and a general dependence of the capacity and degradation rate from the milling energy is examined.Graphical abstractImage 1090
  • Revealing sodium ion storage mechanism in hard carbon
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Stevanus Alvin, Dohyeon Yoon, Christian Chandra, Handi Setiadi Cahyadi, Jae-Ho Park, Wonyoung Chang, Kyung Yoon Chung, Jaehoon Kim Although many studies have demonstrated the excellent potential of hard carbon as an anode in sodium ion batteries, the contribution of its active sites to the capacities of the sloping and plateau voltage regions is not yet clear. Herein, systematical investigation of the relationship between the active sites and sodium ion (Na+) storage in the sloping and plateau voltage regions was presented. In light of the physicochemical properties of the lignin-derived hard carbon (graphitization degree, interlayer spacing, micropore size distribution, and specific surface area), the results of Na+ ion diffusivity, and the change in these properties during Na+ ion insertion/extraction (as characterized by ex situ techniques), new mechanistic insights into Na+ ion storage were proposed. At the beginning of the sodiation process, Na+ ions were adsorbed on defect/edge sites; then partial micropore filling occurred in the sloping region above 0.1 V. In the plateau region below 0.1 V, Na+ ions were intercalated in the graphitic layers, and further adsorption in the micropores occurred near the cutoff potential. Furthermore, sodium clustering occurred below 0.1 V owing to the high concentration of Na+ ions in the micropores.Graphical abstractProposed new sodium ion storage mechanism in hard carbon derived from lignin. At the beginning of the sodiation process, Na+ ions are adsorbed on defect/edge sites; then partial micropore filling occurs in the sloping region above 0.1 V. In the plateau region below 0.1 V, Na+ ions are intercalated in the graphitic layers, and further adsorption in the micropores occurs near the cutoff potential. Furthermore, sodium clustering occurs below 0.1 V owing to the high concentration of Na+ ions in micropores.Image 1
  • Powerful absorbing and lightweight electromagnetic shielding CNTs/RGO
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Luo Kong, Xiaowei Yin, Hailong Xu, Xiaoyan Yuan, Tong Wang, Zhanwei Xu, Jianfeng Huang, Rong Yang, Hua Fan Combination of lightweight and superior electrical conductive performance is charming for the application of macroscopic graphene foam composite. A porous carbon nanotubes/reduced graphene oxide (CNTs/RGO) foam composite are prepared by freeze-drying and in-situ catalytic grown methods. The CNTs/RGO foam composite consists of interconnected RGO nanosheets as the 3D frame and in-situ growth CNTs as the electromagnetic wave (EM) absorbing reinforcement, which grow on graphene substrate. The in-situ grown CNTs on graphene nanosheets lead to the enhancement of conductive and polarization loss, which results in the enhancement of absorption shielding performance. The CNTs/RGO foam composites with different CNT loading are prepared to investigate their EM shielding properties in X-band. The EM shielding effectiveness (SE) of CNTs/RGO foam composite reaches 31.2 dB with 2 mm thickness, especially the specific EMI shielding effectiveness reaches 547 dB cm3/g with an ultralight density of 57 mg cm−3, the absorption is the primary shielding mechanism. Furthermore, SE value reaches 49 dB with thickness of 3.1 mm. Owing to the unique 3D foam hierarchical architecture, light density and outstanding SE performance, our work shows a promising designable approach of preparing CNTs/RGO foam composite to lightweight and absorption type EMI shielding materials.Graphical abstractImage 1063
  • Improved oxygen reduction activity and stability on N, S-enriched
           hierarchical carbon architectures with decorating core-shell iron group
           metal sulphides nanoparticles for Al-air batteries
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Qingshui Hong, Huimin Lu, Yuan Cao To rational design non-noble catalysts with oxygen reduction reaction (ORR) activity and durability superior to that of Pt/C, we report the fabrication of iron group metal sulphides immobilized inside hierarchically porous N,S-enriched carbon architecture using a facile double-phase encapsulation approach followed by a pyrolysis process. The as-prepared hybrid architectures exhibit significantly enhanced electrocatalytic activity towards the ORR, including a positive onset potential, low Tafel slope, and high electron transfer number. In particular, the ORR activity of FeS@G/NSC is even superior to that of the Pt/C benchmark, which possesses an outstanding onset potential (0.99 V vs RHE) and a high discharge voltage plateau (∼1.47 V at discharge current density of 50 mA cm−2 in the Al-air battery test) with excellent stability. These hybrid carbon architectures provide a new direction for carbon-based ORR electrocatalysts performance optimization for next-generation air batteries.Graphical abstractImage 1
  • N-doped graphene confined Pt nanoparticles for efficient
           semi-hydrogenation of phenylacetylene
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Lixin Xia, Dan Li, Jun Long, Fei Huang, Lini Yang, Yushu Guo, Zhimin Jia, Jianping Xiao, Hongyang Liu N-doped graphene (N-graphene) confined Pt nanoparticles (NPs) with core-shell structure supported on carbon nanotubes (CN@Pt/CNTs) are prepared by a facile two-step process. The obtained N-graphene nanoshell ranging from 2 to 4 graphene layers and the Pt NPs covered within N-graphene are uniformly dispersed on the CNTs. The as-prepared CN@Pt/CNTs exhibits much higher styrene selectivity and robust recycle ability in selective hydrogenation of phenylacetylene, compared with that of traditional CNTs supported Pt NPs (Pt/CNTs). DFT calculation reveals that the high styrene selectivity is derived from the confinement effect of N-graphene, which facilitates desorption of styrene from Pt NPs surface, avoiding the over hydrogenation of styrene to benzylethane. The present method paves a new way to design high selective Pt based hydrogenation catalyst.Graphical abstractPt NPs encapsulated within N-doped graphene (N-graphene) supported on carbon nanotubes (CN@Pt/CNTs) exhibits enhanced styrene selectivity and robust recycle ability in selective hydrogenation of phenylacetylene, compared with that of traditional CNTs supported Pt NPs (Pt/CNTs).Image 1
  • Defect-enriched, nitrogen-doped graphitic carbon microspheres within 3D
           interconnected super-macropores as efficient oxygen electrocatalysts for
           breathing Zn-Air battery
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Dan Cheng, Zhe Wang, Chang Chen, Kebin Zhou Constructing efficient bifunctional oxygen electrocatalyst which integrates highly efficient active sites with desired structures for rapid mass transport is of great importance for designing rechargeable Zn-air battery with high power density and fast charge and discharge performances. Herein, defect-enriched N-doped graphitic carbon microspheres with fully open and 3D interconnected super-macropores are successfully constructed by an elaborate coating-activation synthesis strategy. The resulted novel structures are featured with abundant defects as active sites and bicontinuous structures, i.e., the continuous carbon skeleton and the interconnected super-macropores for fast electron and mass transport, respectively. Our synthesized defect-enriched N-doped graphitic carbon microsphere bifunctional oxygen electrocatalysts display excellent performance. The rechargeable Zn-air batteries exhibit a long time charging-discharging cycles as long as 800 cycles at even 50 mA cm−2. This study provides an attractive guide to improve the bifunctional oxygen catalytic performances and promote the Zn-air battery applications in both electric vehicles and grid energy storage in the future.Graphical abstractEfficient defect active sites, bicontinuous structure including 3D interconnected super-macropores and continuous graphite skeleton promote ORR/OER and Zn-air batteries performances.Image 1
  • Position-selective solution phase growth of fullerene crystals
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Chibeom Park, Jinho Lee, Minkyung Lee, Taekyung Yoon, Hee Cheul Choi An efficient method for the formation of hexagonal disk shape C60 crystals at desired positions on a solid substrate has been achieved. The detailed growth behavior was studied through in-situ observation and series of control experiments. Our position selective growth technique enabled a fabrication of bottom electrode type C60 single crystal devices which exhibited n-type field-effect transistor behavior and photo response. Moreover, the C60 single crystal devices were further exploited to study alkali metal doped C60 crystal and its superconductivity.Graphical abstractImage 1
  • Fabrication of high quality and large area graphite thin films by
           pyrolysis and graphitization of polyimides
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Mutsuaki Murakami, Atsushi Tatami, Masamitsu Tachibana We have developed large-area, high-quality graphite thin films that are 0.5–3 μm thick. To prepare the graphite films, we used pyrolysis and graphitization of polyimide up to temperatures in the range 2900 °C-3300 °C, which is applicable to industrial-production processing. Given that the graphite layers of the films are highly oriented in the surface plane, they have good physical properties. The resulting electrical conductivity of graphite film of thickness 1.4 μm and area 10 × 10 cm2 that was treated at 3200 °C is 24,800 S/cm, and the electrical conductivity showed metallic temperature dependence. The carrier mobility of the film is 11,700 V/cm2, and the carrier concentrations of electrons (Ne) and holes (Nh) are 6.98 × 1018 cm−3 and 5.90 × 1018 cm−3, respectively. We consider the high electrical conductivity and mobility to have been derived from the homogeneous, highly oriented graphite layers. We found that graphitization of films less than 3 μm thick progresses uniformly throughout the film, and the resulting graphite films have structures with uniform, highly oriented layers. The produced graphite thin films have excellent physical properties and can be easily handled, so we believe that many industrial applications are possible.Graphical abstractImage 1
  • X3N (X=C and Si) monolayers and their van der Waals Heterostructures with
           graphene and h-BN: Emerging tunable electronic structures by strain
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): Jun Zhao, Hui Zeng, Xingfei Zhou Using density functional theory, we explore the electronic structures of the two-dimensional (2D) C3N and Si3N, as well as C3N-based van der Waals heterostructures with graphene and h-BN. The two-dimensional (2D) C3N is demonstrated to be an indirect semiconductor with atomically flat nanostructure, while the 2D buckled Si3N exhibits metallic property. The semiconductor-metal transition can be obtained under compressive strain of −8% and tensile strain of 14% for the 2D C3N, and the metal-semiconductor transition can be achieved when 10% stretch strain is applied for the Si3N. Moreover, the C3NBN heterojunctions with three different stackings are energetically favorable based on the formation energy analysis. The Dirac-like point of C3N is broken as the interlayer distance is decreased, and the band alignments of the C3NBN heterojunctions are significantly affected by the external strains. In contrast, both AA- and AB-stacked C3N-graphene heterojunctions possess excellent Ohmic contact. The p-type Ohmic contact of the AA stacking can be switched to the n-type provided that the vertical distance is substantially decreased. The tunable electronic properties of the 2D C3N and the comprehensive understanding of C3N-based van der Waals heterostructures influenced by strain engineering may facilitate their practical applications for nanoelectronics and optoelectronics.Graphical abstractImage 1
  • NaClCaOLi2SO4&rft.title=Carbon&rft.issn=0008-6223&">The synthesis of sulfur-doped graphite nanostructures by direct
           electrochemical conversion of CO2 in CaCl2 NaClCaOLi2SO4
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Liwen Hu, Zhikun Yang, Wanlin Yang, Meilong Hu, Shuqiang Jiao The electrochemical synthesis of sulfur-doped nanostructured graphite including graphene and carbon nano-tube via direct electrochemical conversion of CO2 in CaCl2NaClCaOLi2SO4 has been realized at a relative low temperature (675 °C). The results indicate that sulfur can successfully incorporate into carbon matrix and the graphitization degree can also be enhanced by introducing sulfur. In addition to SO42−, Li+ will also have positive effect on improving the graphitization of carbon deposition. Aggregated carbon particles are included in all samples while ultrathin graphite sheet, wire-like carbon, carbon nano-tube and interwoven carbon chains can be obtained in some cases at different electrolytic conditions. This work opens up a novel way to fabricate heteroatom-doped nanostructured carbons from carbon dioxide.Graphical abstractImage 1
  • Electrical characterization of carbon-based fibers and their application
           for sensing relaxation-induced piezoresistivity in polymer composites
    • Abstract: Publication date: April 2019Source: Carbon, Volume 145Author(s): A. Can-Ortiz, J.L. Abot, F. Avilés The direct current (DC) and alternating current (AC) electrical responses of carbon fibers (CFs), carbon nanotube yarns (CNTYs) and glass fibers containing carbon nanotubes (CNTs) on their surface (GF-CNT) are investigated. Under DC, CFs and CNTYs exhibit a nearly Ohmic global response for up to ∼12 μA, although important local variations in the linearity of the current-voltage curves are observed for CNTYs. GF-CNTs, on the other hand, yield a non-Ohmic response. Consistently, under AC, CFs and CNTYs present only a small increase in impedance at high frequencies (∼2 MHz) with larger variations in the phase angle for CNTYs. The discontinuous architecture of the CNT conductive network of GF-CNT yields a rapid and significant decrease of impedance modulus and phase angle as the frequency increases, evidencing microcapacitance effects. Polymeric monofilament composites were manufactured with these three types of fibers, and the piezoresistive behavior induced by viscoelastic relaxation was evaluated. All monofilament composites presented changes in their electrical resistance in response to polymer viscoelastic relaxation, and the sign and magnitude of the electrical resistance change showed a strong dependence on the fiber architecture.Graphical abstractImage 1
  • Fingerprint imaging using N-doped carbon dots
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Ivana Milenkovic, Manuel Algarra, Cristina Alcoholado, Manuel Cifuentes, Juan M. Lázaro-Martínez, Enrique Rodríguez-Castellón, Dragosav Mutavdžić, Ksenija Radotić, Teresa J. Bandosz Carbon Dots (CDs) were obtained using a hydrothermal method and used for the detection of fingerprints through fluorescent imaging. Synthesized CDs exhibited a brightness emission at 495 nm, which was related to their structural and chemical properties. The results of detailed surface characterizations by XPS, ss-NMR and fluorescence spectroscopies, suggested that the negative charge of the functionals groups promoted electrostatic interactions between the charged CDs surface functional groups (amine, amide and carboxylic) and the secretion components present in the thin layer of fluid left on the surface upon its direct contact with human fingers. The obtained results were validated by the scientific protocol of the Police Automated Fingerprint Identification System (AFIS) based on a biometric identification.Graphical abstractImage 1
  • Facile synthesis of N-doped 3D graphene aerogel and its excellent
           performance in catalytic degradation of antibiotic contaminants in water
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Jun Wang, Xiaoguang Duan, Qi Dong, Fanpeng Meng, Xiaoyao Tan, Shaomin Liu, Shaobin Wang 3D nitrogen-doped graphene aerogels (NGA) with hierarchically porous architectures and integrated macrostructures were facilely constructed by self-assembly of graphene oxide (GO) nanosheets and melamine. NGA exhibited excellent catalytic activities in peroxymonosulfate (PMS) activation for oxidative degradation of ibuprofen (IBP). NGA attained 44- and 8-fold enhancement in reaction rate over graphene aerogel (GA) and N-doped reduced graphene oxide (NrGO), respectively. Furthermore, the chemical reactivity of NGA could be facilely recovered by thermal annealing. The superior catalysis of NGA can be ascribed to the synergistic effects of 3D porous framework and N-doping in sp2-hybridized NGA. Graphitic N is demonstrated to be the intrinsic active sites in PMS activation. The 3D porous architecture is beneficial for adsorption and diffusion of the pollutant/oxidant and graphitic carbons within the conjugated π system facilitate the electron transfer. Electron paramagnetic resonance and radical quenching tests indicate that NGA/PMS is a radical-based system, where SO4•− and •OH with strong oxidative potentials account for the catalytic degradation of IBP. This study affords an innovative strategy for development of promising metal-free catalysts towards better advanced oxidation processes.Graphical abstractImage 1
  • Sb2S3 added bio-carbon: Demonstration of potential anode in lithium and
           sodium-ion batteries
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): V. Mullaivananathan, N. Kalaiselvi Activated carbons derived from bio-wastes are quite intriguing, as they possess most of the desirable anodic properties such as larger specific surface area, hierarchical porosity and better electrical conductivity required for exploitation in both LIBs and SIBs. Previously, we have investigated coir pith derived carbon (CPC) which is bestowed with larger specific surface area and uniform distribution of pores for its suitability as energy efficient electrode in electrochemical energy storage systems such as LIBs, SIBs and supercapacitors. As a sequel to our earlier report on the moderate performance of CPC anode this study discusses on the advantages of the composite containing Sb2S3 and CPC in improving the electrochemical performance. Herein, we improved the anodic behavior of CPC, through the incorporation of in-situ formed Sb2S3 obtained from hydrothermal method into the structure of CPC. The CPC/Sb2S3 composite contains ∼11% of Sb2S3 and delivers a capacity of 1100 mA h g−1 at 100 mA g−1 in LIBs and 220 mA h g−1 at 1000 mA g−1 current condition in SIBs. Such a superior electrochemical performance of the composite anode substantiates the synergistic effect of CPC and Sb2S3 in endorsing the suitability of CPC/Sb2S3 anode for use in LIBs and SIBs.Graphical abstractImage 1
  • Facile synthesis of ultrathin interconnected carbon nanosheets as a robust
           support for small and uniformly-dispersed iron phosphide for the hydrogen
           evolution reaction
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Munzir H. Suliman, Alaaldin Adam, Mohammad N. Siddiqui, Zain H. Yamani, Mohammad Qamar Supports play crucial role in determining the catalytic activity, selectivity and overall performance of the supported catalytic nanoassemblies. Herein, ultrathin interconnected carbon nanosheets (CN) are prepared and used as a robust support for dispersion of iron phosphide (FeP) nanoparticles, and the resulting catalytic system is evaluated as low-cost electrocatalyst for hydrogen evolution reaction (HER). Carbon is derived from carbonization of sodium citrate in one-step, which is interconnected and in the form of ultrathin nanosheets (thickness
  • Facile fabrication of highly ordered polyaniline–exfoliated graphite
           composite for enhanced charge storage
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Omer Sadak, M.U. Anu Prathap, Sundaram Gunasekaran A facile method was developed for the fabrication of electrochemically exfoliated graphite (EG) intercalated with polyaniline (PANI) via one-step interfacial polymerization at room temperature to produce a conductive EG-PANI composite. The grafting of PANI nanoparticles on the EG surface was confirmed by microscopy and analytical tests. The EG-PANI exhibited higher areal capacitance (CA) and better electrochemical performance than either EG or PANI. A solid-state asymmetrical supercapacitor (SASc) device was fabricated to evaluate the energy-storage potential of EG-PANI using EG as negative electrode and EG-PANI as positive electrode. The SASc device exhibited high CA (80.4 ± 2.3 mF/cm2) at current density of 1 mA/cm2 and excellent capacitance retention (90.2%) after 1000 galvanostatic charge–discharge cycles at 5 mA/cm2. The specific power and energy density were as high as 4.14 mW/cm2 at current density of 5 mA/cm2 and 9.07 μWh/cm2 at current density of 1 mA/cm2, respectively. After charging just for 10 s at 3.5 V, the output of two SASc devices connected in series illuminated different forward-voltage LEDs for over 5 min without diminished brightness. This work represents a new direction for developing EG intercalated PANI to enhance capacitive efficiency of graphite materials for fabrication of supercapacitors.Graphical abstractExpanded graphite (EG) intercalated with polyaniline (PANI) was synthesized and tested for solid state asymmetric supercapacitor application.Image 1
  • Insight to the synergistic effect of N-doping level and pore structure on
           improving the electrochemical performance of sulfur/N-doped porous carbon
           cathode for Li-S batteries
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Shanxing Wang, Kaixiang Zou, Yunxian Qian, Yuanfu Deng, Lei Zhang, Guohua Chen Three nitrogen-doped porous carbons (NDPCs) with the ultrahigh specific surface areas are prepared via a one-step activation of the biomass waste. The as-prepared samples have different levels of nitrogen contents and pore structure. These sulfur hosting matrix materials are designed to systematically elaborate the effect of N-doping level and pore structure on the electrochemical performance of the S/NDPC nanocomposites. The higher volume ratio of marco-mesopores to micropores of the substrate can greatly enhance the rate capability of the S/NDPC cathodes. This is attributed to the improved electrolyte penetration via the rich marco-mesopores. Meanwhile, the higher nitrogen content of the NDPC contributes to improving the cycle stability of the S/NDPC cathode, which is assigned to the strong chemical adsorption and physical restriction of polysulfides by the interaction of nitrogen atom and polysulfides. Therefore, the S/NDPC-1 cathode, prepared by using a NDPC matrix with high nitrogen content, large specific surface area, and a moderate microporous volume percentage (VMicro/VT), displays an obvious enhancement in the electrochemical performance. It exhibits specific capacities of 926.1 and 815.8 mAh g−1 at 0.5 and 1.0 C rate, respectively, with a capacity fading rate of only 0.067% per cycle after 500 cycles at 1.0 C.Graphical abstractImage 1
  • Improved optical damage threshold graphene Oxide/SiO2 absorber fabricated
           by sol-gel technique for mode-locked erbium-doped fiber lasers
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Zhendong Chen, Hongying Wang, Yonggang Wang, Ruidong Lv, Xiguang Yang, Jiang Wang, Lu Li, Wei Ren In this study, a mode-locked erbium-doped fiber (EDF) laser based on solid-state graphene oxide (GO)-doped sol-gel glass saturable absorber (SA) was designed and tested. The GO-based SA was fabricated for the first time using low-temperature sol-gel technique. Compared to traditional ways of fabricating SAs, the SAs-doped sol-gel glass showed outstanding advantages in terms of high optical damage threshold. The optical damage threshold of SAs-doped sol-gel glass reached as high as 50.69 GW/cm2. X-ray diffractometry (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and annex-energy spectrometry (EDS) identified the main component of prepared sol-gel glass as compact amorphous silicon dioxide. The application of GO-doped sol-gel glass to EDF laser yielded stable mode-locked fiber laser operation. The pulse duration, maximum output power and peak power were recorded as 582 fs, 17.58 mW and 1.30 kW, respectively. Overall, these data indicated that the proposed sol-gel method is promising for fabricating practical SAs for mode-locked fiber lasers.Graphical abstractImage 1
  • Ultrafast terahertz photoresponse of single and double-walled carbon
           nanotubes: Optical pump-terahertz probe spectroscopy
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Srabani Kar, A.K. Sood Photocarrier excitation in conventional semiconductors enhances the conductivity due to increased intraband absorption of terahertz (THz) radiation. We report frequency dependent photoconductivity in terahertz range after 800 nm optical pump excitation in (6,5) semiconducting single-walled carbon nanotubes (SWCNT) and double-walled carbon nanotubes (DWCNT) containing both metallic and semiconducting tubes. The real and imaginary parts of photoconductivity (Δσ(ω)) show non-Drude behavior. In SWCNT, the real part ΔσRe(ω) is positive for low frequency and negative on the high-frequency side of the terahertz spectra. In contrast, DWCNTs show negative ΔσRe(ω) on low frequency and positive on the high-frequency side. This contrasting behavior is explained using Boltzmann transport theory, where the carrier scattering rate is energy dependent. Taking the scattering rate to be dominated by short-range disorder scattering, we show that the Boltzmann transport model captures the unique experimental features of Δσ(ω), for SWCNT as well as DWCNT. Both the semiconducting and metallic nanotubes in DWCNT are shown to contribute to the observed photoconductivity.Graphical abstractImage 1
  • Graphene multi-protonation: A cooperative mechanism for proton permeation
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Massimiliano Bartolomei, Marta I. Hernández, José Campos-Martínez, Ramón Hernández-Lamoneda The interaction between protons and graphene is attracting a large interest due to recent experiments showing that these charged species permeate through the 2D material following a low barrier (∼ 0.8 eV) activated process. A possible explanation involves the flipping of a chemisorbed proton (rotation of the CH+ bond from one to the other side of the carbon layer) and previous studies have found so far that the energy barriers (around 3.5 eV) are too high to explain the experimental findings. Contrarily to the previously adopted model assuming an isolated proton, in this work we consider protonated graphene at high local coverage and explore the role played by nearby chemisorbed protons in the permeation process. By means of density functional theory calculations exploiting large molecular prototypes for graphene it is found that, when various protons are adsorbed on the same carbon hexagonal ring, the permeation barrier can be reduced down to 1.0 eV. The related mechanism is described in detail and could shed a new light on the interpretation of the experimental observations for proton permeation through graphene.Graphical abstractImage 1
  • Three-dimensional micron-porous graphene foams for lightweight current
           collectors of lithium-sulfur batteries
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Liqiang Lu, Jeff Th. M. De Hosson, Yutao Pei This paper reports a three-dimensional (3D) stochastic bicontinuous micron-porous graphene foam (3D-MPGF) developed as lightweight binder-free current collectors for sulfur cathodes of lithium-sulfur batteries. 3D-MPGF is synthesized by a facile process that originally combines the synthesis of porous metals by the reduction of metallic salts and chemical vapor deposition (CVD) growth of graphene in a continuous route. 3D-MPGF presents micron-porous structure with both interconnected tubular pores and nontubular pores of sizes from hundreds nanometers to several microns. By adjusting CVD time, the thickness of graphene wall is tunable from few atomic layers to ten layers. Raman results prove a high crystalline of 3D-MPGF. Attributed to the low density and high quality, 3D-MPGF can be used as promising lightweight binder-free current collectors. The 3D-MPGF loaded with S of 2.5 mg cm−2 exhibited an ultrahigh initial capacity of 844 mAh g−1 (of electrode), and maintain at 400 mAh g−1 after 50 cycles at 0.1C (167 mA g−1). With increasing the loading of S, the electrodes present higher areal capacities. When the loading of S is 13 mg cm−2, the areal capacity of 3D-MPGF/S reaches 5.9 mAh cm−2 after 50 cycles at 0.1C. The use of 3D micron-porous graphene foam proves considerably enhanced gravimetric capacity densities (of overall electrode), which can be a direction not only for batteries but also for other energy storage devices.Graphical abstractImage 1
  • Heavily nitrogen doped chemically exfoliated graphene by flash heating
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Seol Yoo, Soo Yeon Jeong, Jae-Won Lee, Jong Hwan Park, Doo-Won Kim, Hee Jin Jeong, Joong Tark Han, Geon-Woong Lee, Seung Yol Jeong Heteroatom doping can enhance the electrochemical properties of graphene. However, unstable CN bonding at high temperature limits the concentration of nitrogen dopants. Intense pulsed light (IPL) was used to prepare heavily nitrogen-doped reduced graphene oxide (NrGO). Unlike general heating methods like thermal annealing, IPL provides ultrafast direct heating and cooling in the graphene layers because they serve as the heating source after light absorption. As this heat originates from the photothermal effect of surface plasmons on the graphene layers, nitrogen precursors are effectively decomposed. The fast cooling also generates a corrugated graphene structure with high specific surface area owing to thermal quenching. The electronic and structural properties of flash-heated NrGO (FH-NrGO) were investigated by X-ray photoelectron spectroscopy, Raman spectroscopy, and ultraviolet photoelectron spectroscopy, which revealed a high total nitrogen content of 26 at.% after flash heating at 1500 °C. Moreover, the nitrogen content could be varied by controlling the irradiation energy, and the electrochemical performance of FH-NrGO was better than that of NrGO prepared by general heating. Therefore, flash heating by IPL can be used to produce heavily nitrogen-doped graphene with superior electrochemical performance as an anode material for energy-storage devices.Graphical abstractFlash heating method was used to prepare heavily nitrogen-doped reduced graphene oxide (NrGO). Unlike general heating methods like thermal annealing, this method provides ultrafast direct heating and cooling in the graphene layers because they serve as the heating source after light absorption. This easy and straightforward method offered doping of graphene layers with a high concentration of about 26 at.% of nitrogen in a few milliseconds.Image 1
  • Gradients of microstructure, stresses and mechanical properties in a
           multi-layered diamond thin film revealed by correlative cross-sectional
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): David P. Gruber, Juraj Todt, Nicolas Wöhrl, Jakub Zalesak, Michael Tkadletz, Adam Kubec, Sven Niese, Manfred Burghammer, Martin Rosenthal, Hadwig Sternschulte, Manuel J. Pfeifenberger, Bernhard Sartory, Jozef Keckes Thin diamond films deposited by chemical vapour deposition (CVD) usually feature cross-sectional gradients of microstructure, residual stress and mechanical properties, which decisively influence their functional properties. This work introduces a novel correlative cross-sectional nano-analytics approach, which is applied to a multi-layered CVD diamond film grown using microwave plasma-enhanced CVD and consisting of a ∼8 μm thick nanocrystalline (NCD) base and a ∼14.5 μm thick polycrystalline (PCD) top diamond sublayers. Complementary cross-sectional 30 nm beam synchrotron X-ray diffraction, depth-resolved micro-cantilever and hardness testing and electron microscopy analyses reveal correlations between microstructure, residual stress and mechanical properties. The NCD sublayer exhibits a 1.5 μm thick isotropic nucleation region with the highest stresses of ∼1.3 GPa and defect-rich nanocrystallites. With increasing sublayer thickness, a 110 fibre texture evolves gradually, accompanied by an increase in crystallite size and a decrease in stress. At the NCD/PCD sublayer interface, texture, stresses and crystallite size change abruptly and the PCD sublayer exhibits the presence of Zone T competitive grain growth microstructure. NCD and PCD sublayers differ in fracture stresses of ∼14 and ∼31 GPa, respectively, as well as in elastic moduli and hardness, which are correlated with their particular microstructures. In summary, the introduced nano-analytics approach provides complex correlations between microstructure, stresses, functional properties and deposition conditions.Graphical abstractImage 10773
  • Structure evolution in all-aromatic,
           poly(p-phenylene-vinylene)-derived carbon fibers
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Michael R. Buchmeiser, Erna Muks, Roman Schowner, Erik Frank, Ulrich Hageroth, Sabine Henzler, Johanna Spörl, Antje Ota, Ronald Beyer, Alexandra Müller Carbon fiber (CF) structure is strongly influenced in terms of CF's crystallinity, crystallite dimensions, orientation, and interlayer spacing by the structure of the CF precursor, including its sp2/sp3 carbon content, and the process parameters for spinning, oxidative stabilization, and carbonization/graphitization. In order to retrieve information about structure formation in all-aromatic CF precursors, poly(p-phenylene-vinylene) (PPV) fibers have been prepared through dry spinning of a sulfinyl-based precursor polymer followed by thermal conversion into PPV. By applying different stretch ratios, different degrees of orientation were realized. Subsequent thermal conversion of these PPV fibers into CFs with and without additional tension during carbonization allowed for following structure formation in the final CFs. Wide-angle X-ray scattering and Raman data were recorded at different stages of carbonization and compared to those of a poly(acrylonitrile)-derived CF as well as to lignin- and cellulose-derived CFs. Structure formation during carbonization was correlated with the sp2/sp3 carbon content of the CF precursors. The all-sp2 carbon precursor PPV was found to favor crystallite growth in the direction of the CF axis, parallel to the individual graphite planes, and formation of ordered graphitic structures at an earlier stage and to a higher extent than in high-/all-sp3 carbon precursors.Graphical abstractImage 1
  • Self-hybridized coralloid graphitic carbon nitride deriving from deep
           eutectic solvent as effective visible light photocatalysts
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Xiang Yu, Tingting Fan, Wenwen Chen, Zhou Chen, Yunyun Dong, Hongqiang Fan, Weiping Fang, Xiaodong Yi The room temperature deep eutectic solvent (DES) is demonstrated as an ideal precursor to prepare self-hybridized graphitic carbon nitride (g-C3N4) for the first time, for its special components, randomly reorganized molecules and extensive hydrogen bonds. In this work, by adjusting the proportion of urea and ammonium thiocyanate in the precursor DES, the self-hybridized coralloid g-C3N4, stacked by a mass of double-layer g-C3N4/g-C3N4 nanocages, were prepared without any templates. Compared to conventional g-C3N4 prepared using melamine, urea and AT as precursors, the improved charge transfer between the interfaces of the self-hybridized g-C3N4 has been demonstrated, which is attributed to the well-matched electronic band structures of the two g-C3N4 species, the abundant 2D/2D interfacial contact and increased photocatalytic active sites. As expected, it exhibits highly enhanced photocatalytic activity, which is among the best g-C3N4 photocatalysts without doping any other elements.Graphical abstractImage 1
  • A hierarchical porous Fe-N impregnated carbon-graphene hybrid for
           high-performance oxygen reduction reaction
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Sihui Wang, Xiao Yan, Kuang-Hsu Wu, Xuemin Chen, Jian-Min Feng, Pengyi Lu, Hui-Ming Cheng, Hui-Ming Cheng, Ji Liang, Shi Xue Dou A Fe-N impregnated carbon in a hybrid with in-situ grown graphene from hierarchical porous carbon has been obtained for high-performance oxygen reduction reaction (ORR) catalysis. This hybrid material combines the desirable characteristics for the ORR, including Fe-N active sites, high surface area, good electron conductivity, and hierarchical channels for mass diffusion. As a result, this catalyst exhibits a very positive reaction onset potential (−0.05 V vs. Ag/AgCl), a high ORR current density, and a complete four-electron ORR pathway, which are even better than a commercial 20% Pt/C catalyst. We further reveal the synergistic ORR enhancement from the controlled Fe-N impregnation in the doped carbon-graphene hybrid.Graphical abstractA hierarchical porous Fe-N impregnated carbon-graphite has been obtained, which carries outstanding ORR catalytic capability even better than the state-of-the-art Pt/C catalyst in an alkaline electrolyte. The excellent performance of this hybrid material can be attributed to the Fe-N active sites, high surface area, good electron conductivity, and hierarchical channels for facile mass diffusion.Image 1
  • Candle soot: Journey from a pollutant to a functional material
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Manasi R. Mulay, Aditya Chauhan, Satyanarayan Patel, Viswanath Balakrishnan, Aditi Halder, Rahul Vaish Candle soot, traditionally considered as an unwanted source of air-pollution, has slowly been phased out by modern lighting techniques. However, a 2007 study by Liu and co-workers first brought to light the presence of fluorescent carbon nanoparticles (CNPs) in untreated candle-soot (CS). Subsequent studies revealed that these soot-generated CNPs can be refined and extracted for various applications including humidity sensing, trace element detection and biomedical to Li-ion batteries, supercapacitors, electrocatalysis and solar collector among others. There are over 100 published articles dealing with fabrication, extraction, treatment and application of CS derived CNPs. However, unlike traditional carbon-based nanostructures including graphene and fullerene, this field lacks the presence of a systematic endeavour to tap into the vast potential of candle-soot. Therefore, this article aims to present a focused review on the topic of CS derived CNPs and their potential applications. The paper starts with a brief introduction on the topic of candle-soot and its historic significance. This is followed by a description of the techniques used to extract, refine and functionalize these carbon particles. Thereafter the reported applications of candle-soot derived nanostructures and their comparative analysis with the current state-of-art are provided. Finally, a section discussing future scopes and challenges is presented followed by conclusions.Graphical abstractImage 1
  • The physics of single-side fluorination of graphene: DFT and DFT + U
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): F. Marsusi, N.D. Drummond, M.J. Verstraete We present density functional theory (DFT) calculations of the electronic and magnetic properties of fluorine adatoms on a single side of a graphene monolayer. By extrapolating the results, the binding energy of a single fluorine adatom on graphene in the dilute limit is calculated. Our results confirm that the finite-size error in the binding energy scales inversely with the cube of the linear size of the simulation cell. We establish relationships between stability and CF bond nature, diffusion of fluorine adatoms and total magnetization in different configurations of adatoms. For single-side fluorination, sp2.33 is the maximum p-content re-hybridization found in the CF bond. We show that semilocal DFT cannot predict correctly the magnetic properties of fluorinated graphene and a higher level theory, such as DFT + U is needed. The results indicate a tendency of graphene to reduce the imbalance between adsorption on the two sublattices, and therefore total magnetization, through low-energy-barrier pathways on a time scale of ∼10 ps at room temperature. The thermodynamically favored arrangements are those with the smallest total magnetization. Indeed, the electronic structure is intimately related to the magnetic properties and changes from semi-metallic to p-type half-metallic or semiconducting features, depending on the adatoms arrangement.Graphical abstractImage 1
  • Magneto-electronic and optical properties of Si-doped graphene
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Po-Hsin Shih, Thi-Nga Do, Bor-Luan Huang, Godfrey Gumbs, Danhong Huang, Ming-Fa Lin The rich and unique magnetic quantization phenomena of Si-doped graphene defect systems for various concentrations and configurations are fully explored by using the generalized tight-binding model. The non-uniform bond lengths, site energies and hopping integrals, as well as a uniform perpendicular magnetic field (Bzzˆ) are taken into account simultaneously. The quantized Landau levels (LLs) are classified into four different groups based on the probability distributions and oscillation modes. The main characteristics of the LLs are clearly reflected in the magneto-optical selection rules which cover the dominating Δn= nv−nc =0, the coexistent Δn=0 and Δn=1, along with the specific Δn=1. These rules for inter-LL excitations are attributed to the non-equivalence or equivalence of the Ai and Bi sublattices in a supercell. The spectral intensity can be controlled by oscillator strength using a canonical momentum (vector potential) as well as by density of states using concentration and distribution of doped Si atoms.Graphical abstractThe novel magneto-optical selection rules in graphene with Si-doped defect.Image 1
  • Detecting the major charge-carrier scattering mechanism in graphene
           antidot lattices
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Dongchao Xu, Shuang Tang, Xu Du, Qing Hao Charge carrier scattering is critical to the electrical properties of two-dimensional materials such as graphene, black phosphorene, and tellurene. Beyond pristine two-dimensional materials, further tailored properties can be achieved by nanoporous patterns such as nano- or atomic-scale pores (antidots) across the material. As one example, structure-dependent electrical/optical properties for graphene antidot lattices (GALs) have been studied in recent years. However, detailed charge carrier scattering mechanism is still not fully understood. In this paper, the energy sensitivity of charge-carrier scattering and thus the dominant scattering mechanisms are revealed for GALs by analyzing the maximum Seebeck coefficient with a tuned gate voltage and thus shifted Fermi levels. It shows that the scattering from pore-edge-trapped charges is dominant. For thermoelectric interests, the gate-voltage-dependent power factor for a GAL with the square pattern can reach as high as 554 μW/cm⋅K2 at 400 K. With their high thermal conductivities and power factors, these GALs can be well suitable for “active coolers” within electronic devices, where heat generated at the hot spot can be removed with both passive heat conduction and active Peltier cooling.Graphical abstractMeasurement setup of GAL samples. The gate-voltage-dependent power factor of a GAL with the square pattern is measured as high as 554 μW/cm K2 at 400 K on the hole side.Image 1
  • Fabrication of bimodal micro-mesoporous amorphous carbon-graphitic
           carbon-reduced graphene oxide composite microspheres prepared by
           pilot-scale spray drying and their application in supercapacitors
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Ha-Na Kwon, Gi Dae Park, Yun Chan Kang, Kwang Chul Roh There has been a demand for a suitable method which is applicable to mass production of electrode materials for supercapacitor. Herein, the synthesis of amorphous carbon–graphitic carbon-reduced graphene oxide (AC-GC-rGO-a) composite microspheres by pilot-scale spray drying/KOH activation is described and their performance as an electrode material is examined. Through pilot-scale spray drying in a 2 m high chamber, large-scale production of precursor (Fe nitrate-dextrin-GO composite) microspheres is realizable. Metallic Fe nanocrystals formed by carbothermal reduction play a role in the transformation of the dextrin-derived amorphous carbon into graphitic carbon layers. Micropores are then formed from the dextrin-derived amorphous carbon by KOH activation, and finally, bimodal pore-structured AC-GC-rGO-a composite microspheres are prepared. In particular, it is revealed that crumpling of the rGO increases the electrical conductivity of the composite microspheres and thus results in a large specific capacitance (408.2 F g−1) and enhanced rate performance. Additionally, AC-GC-rGO-a features improved cycling stability, exhibiting a capacity retention of 94.7% after 10,000 cycles at 10 mA g−1. Therefore, the developed composite surpasses other carbon materials and graphene oxide composites and is potentially suitable for mass production.Graphical abstractImage 1
  • Melamine assisted liquid exfoliation approach for the synthesis of
           nitrogen doped graphene-like carbon nano sheets from bio-waste bagasse
           material and its application towards high areal density Li-S batteries
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Dasari Bosu Babu, Kannadka Ramesha Li-S battery has received considerable attention as futuristic technology, however, solutions for challenging problems such as polysulfide shuttle and low sulfur loadings, etc. still remain elusive. Here we report design of efficient polysulfide trap by preparing graphene like nitrogen doped carbon (NBC) sheets from bagasse (sugarcane waste). Further, we prepared S@NBC composites by chemical absorption of S onto NBC matrix and studied their beneficial aspects as cathode for Li-S battery. The S@NBC displays extraordinarily good performance with a reversible capacity of 1169 mAh g−1 at 0.2 C with 77% capacity retention after 200 cycles which also exhibits remarkable 85% retention of higher order polysulfide even after 200 cycles. Moreover, by placing a second cathode layer the cyclability will be increased beyond 500 cycles. The remarkable cycling performance is attributed to the effective chemisorption of sulfur and polysulfides by the nitrogen doped carbon. Further, sulfur loading is increased to 12 mg cm−2 by stacking four cathode layers and we could achieve high areal capacity of 12 mAh cm−2 which is three times higher than the present day lithium ion battery.Graphical abstractImage 1
  • Alveolate porous carbon aerogels supported Co9S8 derived from a novel
           hybrid hydrogel for bifunctional oxygen electrocatalysis
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Xuejiao Hu, Yifan Chen, Mengru Zhang, Gengtao Fu, Dongmei Sun, Jong-Min Lee, Yawen Tang Incorporation of transition-metal dopants into carbon aerogels is a powerful way to develop highly-active and robust bifunctional oxygen electrocatalysts. Herein, we develop a novel hybrid hydrogel method for the preparation of Co9S8-doped alveolate carbon aerogels. The hydrogel formation depends on a simple sol−gel polymerization of chitosan, sodium tripolyphosphate and polyhexamethyleneguanidine phosphate. The repeating units of polymer contain a binding site (NH2) for Co2+ ions, after pyrolysis which ensures a uniform anchor of Co9S8 particles within the carbon aerogels. The newly developed catalyst exhibits excellent bifunctional activity and robust stability for both the oxygen reduction reaction and oxygen evolution reaction, resulting from the significant synergy between Co9S8 and 3D porous N, P-codoped carbon aerogels. Moreover, we also demonstrate that Co9S8 material is more active to OER than to ORR through the density functional theory (DFT) theoretical computation.Graphical abstractImage 1
  • Doping modulation of quasi-free-standing monolayer graphene formed on
           SiC(0001) through Sn1-x Ge x intercalation
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Hidong Kim, Otgonbayar Dugerjav, Altaibaatar Lkhagvasuren, Jae M. Seo In order to modulate the transfer doping of quasi-free-standing monolayer graphene (QFMLG) formed on SiC(0001), Ge atoms were intercalated additionally into QFMLG already formed by Sn intercalation between ZL and 6H-SiC(0001). By postannealing the Ge-deposited surface at 600 °C, the Sn1-xGex film with the 4×33 structure, composed of a bilayer and adatoms with dangling bonds under QFMLG, has been formed. It turns out that, in this Sn1-xGex film, Ge atoms preferentially occupy the bottom layer bound to the top Si atoms of the substrate, while Sn atoms occupy the top adatom sites. Strong correlation among the electrons localized at these adatom sites induces a semiconducting alloy film. As the postannealing temperature is increased up to 800 °C, the concentration of Ge in the intercalated film of the same 4×33 structure is gradually increased and the Dirac point also shifts gradually from −0.16 eV to +0.20 eV relative to the Fermi level. Such a result confirms that the transfer doping of QFMLG on SiC(0001) has been modulated by varying the alloy composition of the Sn1-xGex interfacial film.Graphical abstractImage 1
  • Novel porous carbon nanosheet derived from a 2D Cu-MOF: Ultrahigh porosity
           and excellent performances in the supercapacitor cell
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Zuo-Xi Li, Bo-Long Yang, Kang-Yu Zou, Lingjun Kong, Man-Li Yue, Hui-Hui Duan In this work, a novel Cu-MOF of translational 2D (4,4) layers has been designed and afforded as hierarchically stacking lamellae with interspace. Cu-MOF is initially employed as precursors to prepare the Cu@C composite through calcination-thermolysis procedure. Then Cu@C is etched with HCl, and subsequently activated by KOH to obtain APC with nanosheet morphology, which shows ultrahigh BET specific surface area (2491 m2 g−1) and pore volume of 1.50 cm3 g−1 (Vmirco = 0.12 cm3 g−1, Vmeso+macro = 1.38 cm3 g−1). Significantly, the APC nanosheet owns outstanding specific capacitance of 260.5 F g−1 at 0.5 A g−1 under a load of 8 mg/cm2. SSC based on APC achieves excellent specific energy density of 18.38 W h Kg−1 at specific power density of 350 W kg−1. Our SSC still retains 91.1% of original capacitance after 5000 cycles, exhibiting remarkable long-term cycle and reversibility. Amazingly, a red LED can be lighted up by three SSCs over 12 min. Therefore, the APC nanosheet is a competitive and promising candidate for preparing supercapacitor cells.Graphical abstractOne novel 2D Cu-MOF is employed as a precursor to prepare the APC nanosheet with interspace through the calcination-thermolysis strategy, which presents ultrahigh BET specific surface area and excellent supercapacitance. Furthermore, SSC based on the APC nanosheet shows remarkable energy density under high power density, and a red LED can be lighted up by three SSCs over 12 min.Image 1
  • Carbon nanotube/carbon composite fiber with improved strength and
           electrical conductivity via interface engineering
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Songlin Zhang, Ayou Hao, Nam Nguyen, Abiodun Oluwalowo, Zhe Liu, Yourri Dessureault, Jin Gyu Park, Richard Liang Carbon nanotube/carbon (CNT/C) composites show potential for lightweight structural materials and non-metal electrical conductors for aerospace, military, and other industries where the combination of lightweight, high strength and excellent conductivity are required. Most research attempts have been reported to fabricate CNT/C composite focusing on the high CNT alignment and dense carbon matrix. However, simultaneous improvement of strength and electrical conductivity in materials still presents a great challenge. In this study, pyrolyzed polydopamine (py-PDA) with selected surface treatments is introduced as an interface enhancer between CNTs and the carbon matrix. Due to the presence of py-PDA, the effective physical interlocking and conductive pathways are rebuilt at the interface area between CNTs and carbon matrix, resulting in better load transfer and electron transport. The CNT/py-PDA/C composite fibers demonstrated remarkable improvements in electrical conductivity (2.1 × 103 S cm−1 or 228 S m2 kg−1) and tensile strength (up to 727 MPa or 790 MPa/(g·cm−3)), which should prove to be vastly advantageous as compared to the previously reported CNT/C composites. The outstanding thermal stability of fully carbonized materials is also an attractive feature. Coupled with scalable manufacturing methods, these integrated characteristics of CNT/py-PDA/C composite fiber can potentially have broad applications for lightweight structural materials and non-metal conductors.Graphical abstractImage 1
  • High performance wire-type supercapacitor with Ppy/CNT-ionic
           liquid/AuNP/carbon fiber electrode and ionic liquid based electrolyte
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Changhoon Song, Junyeong Yun, Kayeon Keum, Yu Ra Jeong, Heun Park, Hanchan Lee, Geumbee Lee, Seung Yun Oh, Jeong Sook Ha We report a fabrication of a high-performance wire-type supercapacitor through surface modification of carbon fiber with ionic liquid, nanomaterials, and gel electrolyte containing ionic liquid. Coating of Au nanoparticles onto carbon fiber increases both surface area and electrical conductivity. Dip-coating of mixture of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), carbon nanotubes, and electropolymerization of polypyrrole (Ppy) onto Au coated fiber for pseudocapacitance results in high capacitance. The use of propylene carbonate-poly(methyl methacrylate)-[EMIM][TFSI] gel electrolyte gives high operation voltage. Such wire-type supercapacitor exhibits a high voltage of 2.5 V, an areal capacitance of 38.49 mF cm−2, and a maximum energy and power density of 24.7 μWh cm−2 and 3.52 mW cm−2, respectively. In addition, the cyclic stability of the supercapacitor is dramatically enhanced by using 2-naphthalene sulfonic acid as a dopant in electropolymerization of Ppy. Encapsulation with a thermally shrinkable tube endows the supercapacitor with mechanical stability and waterproof features when it is bent, folded, twisted, even in water. This work demonstrates high potential of such wire-type supercapacitor as a flexible energy-storage device for various applications, especially those that require high voltage.Graphical abstractImage 1
  • Constructing flexible coaxial-cable structured sulfur cathode with carbon
           nanomaterials on textile
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Peibo Gao, Xi Huang, Dingcheng Cen, Zhihao Bao Lithium-sulfur battery is an attractive energy storage system owing to its high theoretical capacity. However, the insulating nature of sulfur and “shuttle effect” of intermediate lithium polysulfides hinders its practical utilization. Herein, we demonstrate a facile dip-coating process to construct coaxial-cable carbon structure directly on the fibers of textile as sulfur host. Specifically, textile is dip-coated in the suspension of CNTs, CNT/sulfur hybrid and graphene in sequence. After drying, three corresponding layers are spontaneously formed on the fibers of the textiles due to Van der Waals force. The composite cathode delivers a reversible discharge capacity as high as 913.0 mA h g−1 at 0.5 C and excellent cycling stability with a retention rate of 88% after 200 cycles with a sulfur loading of 3 mg cm−2. The excellent performance is ascribed to the high absorption capability of polysulfides in the hierarchical porous structures, excellent conductivity of CNT, and effective shuttle suppression of polysulfides by graphene sheet. The process reported in this work can provide a new way to synthesize flexible and robust sulfur cathode for LiS battery application.Graphical abstractImage 1
  • Low-damage nitrogen incorporation in graphene films by nitrogen plasma
           treatment: Effect of airborne contaminants
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Germain Robert Bigras, Xavier Glad, Leron Vandsburger, Carl Charpin, Pierre Levesque, Richard Martel, Luc Stafford Graphene films grown on copper by chemical vapor deposition were exposed to the late afterglow of a reduced-pressure N2 plasma sustained by microwave electromagnetic fields. X-ray photoelectron and Raman spectroscopies reveal extremely high incorporation of plasma-generated N atoms into the graphene film (N/C = 29%) while maintaining an unprecedentedly low-damage generation (D:G = 0.35–0.45) compared to the literature (0.5–2.5). The incorporation dynamics between graphene on copper and graphene on copper oxide are also compared and discussed. After transfer on SiO2/Si substrate, the N/C content decrease to only 6%. This reveals that a large part of the N atoms are weakly bonded to the graphene surface. Most of the nitrogen incorporation seems linked to the functionalization of weakly bonded hydrocarbons initially adsorbed from air exposure or carbon-nitrogen structures arising from plasma-surface interactions.Graphical abstractImage 1
  • Time-resolved photoluminescence of pH-sensitive carbon dots
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Nabaruna Basu, Debabrata Mandal Time-resolved photoluminescence emission were performed to study the ≥100 ps time-scale photophysics of water soluble carbon dots (CDs) dispersed in different pH solutions. Excitation of the core and high-energy edge states at excitation wavelengths λex ≤ 350 nm produce hole-electron excitonic charge-carriers but do not yield any photoluminescence emission, implying efficient non-radiative recombination mechanisms for the charge-carriers. Using λex ∼375 nm, surface fluorophores as well as low-lying edge-states are excited, producing emission over a broad range. However, the emission characteristics vary strongly depending on the pH condition and the choice of excitation wavelength. In particular, the edge state emission is abruptly extinguished at pH ≥ 5, which also marks the onset of deprotonation of surface-bound -COOH groups of the CDs, indicating that the -COO- anionic centers promote quenching of edge-state emission. Using λex ∼450 nm, only the surface fluorophores are excited. The deprotonation of phenolic -OH group at pH > 9 causes a sharp red-shift in the emission spectra at all excitation wavelengths. The pH-sensitive emission behavior of the CDs enable them to serve as optical pH sensors.Graphical abstractImage 1
  • Synergistic effect of CB and MWCNT on the strain-induced DC and AC
           electrical properties of PVDF-HFP composites
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Kaiyan Huang, Huiming Ning, Ning Hu, Xiaopeng Wu, Shu Wang, Shayuan Weng, Weifeng Yuan, Alamusi, Liangke Wu, Yaolu Liu In this study, carbon black (CB)/multi-walled carbon nanotube (MWCNT)/polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) composite films were fabricated as strain sensors. The sensing characteristics of the composite films both in the direct current (DC) and alternating current (AC) circuits were systematically tested. It was found that the hybrid nanofiller could effectively improve both the electrical conductivity and the sensitivity of the nanocomposites at a given loading far below the percolation threshold of a single filler. At 3.0% tensile strain, the highest DC and AC gauge factors for the nanocomposites with 1.0 wt.% CB and 0.1 wt.% MWCNT were 10.67 and 10.38, respectively, which were 1992.2% and 75.9% higher than those of the composites filled with 2.0 wt.% CB only. In addition, both the relationship of the strain-resistance change rate in the DC condition and the strain-DLT (the dielectric loss tangent) change rate in the AC condition of the nanocomposites with the hybrid nanofiller showed an approximatively linear characteristic, which demonstrated that the linearity of the nanocomposite sensor could be controlled by properly adjusting the content of CB and MWCNT. Finally, the mechanism of the synergistic effect was investigated by inspecting the microstructure of the nanocomposites and an equivalent RLC circuit model.Graphical abstractImage 10241
  • Growth of epitaxial CdTe thin films on amorphous substrates using single
           crystal graphene buffer
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Dibyajyoti Mohanty, Zonghuan Lu, Xin Sun, Yu Xiang, Lei Gao, Jian Shi, Lihua Zhang, Kim Kisslinger, Morris A. Washington, Gwo-Ching Wang, Toh-Ming Lu, Ishwara B. Bhat Traditionally, a high-quality CdTe film can only be grown on a single crystal substrate with a small lattice mismatch. Herein, we report the epitaxy of CdTe films on monolayer single crystal graphene buffered amorphous SiO2/Si(100) substrates, despite a 86% lattice mismatch between CdTe(111) and graphene. X-ray pole figure, electron backscatter diffraction mapping and transmission electron microscopy all confirm that the epitaxial CdTe films are composed of two domains: the primary and the Σ3 twin. The crystal quality of films is shown to improve as the post-deposition annealing temperature increases. However, the rotational misalignment in CdTe remains large even after annealing. Through density functional theory calculations on the charge transfer distribution at the interface of CdTe and graphene, it is found that the interface is dominated by the weak van der Waals interaction, which explains the large spread of in-plane orientation in CdTe films. Furthermore, the rotational misalignment in graphene itself is also confirmed to produce the large in-plane orientation spread in CdTe films. Although imperfect in epitaxy quality, this work demonstrates that monolayer single crystal graphene can buffer amorphous substrates for growing epitaxial films, and hence hints an opportunity for developing advanced thin film devices using graphene as a template.Graphical abstractImage 1
  • Electrical and acoustic vibroscopic measurements for determining carbon
           nanotube fiber linear density
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Robert J. Headrick, Mitchell A. Trafford, Lauren W. Taylor, Oliver S. Dewey, Russell A. Wincheski, Matteo Pasquali Lightweight materials for next-generation electrical and mechanical applications are expected to have significant impacts on aerospace and ground transportation by reducing fuel consumption. Assessing the potential of novel wiring or fibers requires accurate measurement of linear density. The linear densities of fibers are measured by determining the fiber's resonant frequency vibroscopically, which requires complex mechanical equipment for vibrating the fiber. Here, we leverage the electrical conductivity of carbon nanotube (CNT) fibers to induce vibrations by applying an alternating current (AC) to a fiber under a known tension in the presence of a permanent magnetic field, eliminating the need for mechanical actuation. The fiber vibrates at maximum amplitude when the AC frequency matches the fiber's fundamental resonant frequency, creating an audible sound and inducing measurable changes in the fiber electrical properties. Linear density can be calculated accurately from the resonant frequency or the changes in electrical properties in this simplified apparatus during a tensile test.Graphical abstractImage 1
  • Combustion enhancement of hydroxyl-terminated polybutadiene by doping
           multiwall carbon nanotubes
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Suhang Chen, Yue Tang, Hongsheng Yu, Xinyan Guan, Luigi T. DeLuca, Wei Zhang, Ruiqi Shen, Yinghua Ye Hydroxyl-terminated polybutadiene (HTPB) is extensively used in propulsion; however, it's trapped in low regression rate, partly related to poor thermal transfer from combustion. Carbon nanotubes (CNT) act as an energy transfer media, potentially accelerating the heat transfer and combustion performance of HTPB. Herein, multiwall CNT (MWCNT)/HTPB composites were prepared by dispersing MWCNT and surfactant into HTPB and toluene solvent through ball milling. Low MWCNT content (≤1%) promoted combustion, and excess MWCNT (≥2%) depressed, despite MWCNT shifting the HTPB-O2 reaction to higher temperatures. (0.5%, 1%, 2% and 3%) MWCNT/HTPB composites reinforced the instantaneous regression rate by 11.2%, 31.6%, −21.3%, and −39.7% at Gox = 365 kg/m2·s; by 27.0%, 25.0%, −26.4%, and −36.6% at Gox = 150 kg/m2·s; while strengthened the average regression rate by 0.9%, 8.5%, −17.4%, and −36.7% at Gox = 365 kg/m2·s; and by 5.4%, 8.9%, −8.3%, −22.6% at Gox = 100 kg/m2·s. Specifically, the optimal MWCNT level was 1%, as demonstrated by the optimized reinforced thermal conductivity and slightly reduced energy release, since excessive MWCNT (>2%) hinders combustion through heat dissipation, high viscosity of the melting layer, low energy release and an attached carbon layer on the burning surface blocking the energy transfer.Graphical abstractImage 1
  • N-doped carbon shell coated CoP nanocrystals encapsulated in porous
           N-doped carbon substrate as efficient electrocatalyst of water splitting
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Zhuo Peng, Yang Yu, Dan Jiang, Yule Wu, Bao Yu Xia, Zehua Dong Water electrolysis is of great importance for high-efficient hydrogen production. Replacing noble metal-based electrocatalysts by highly efficient and inexpensive non-noble metal based catalysts is critical for the practical application of these technologies. Here we report a novel hybrid of nitrogen-doped carbon shell coated CoP nanocrystals encapsulated in porous nitrogen-doped carbon substrate (CoP/PNC), which is synthesized through sol-gel and consequent pyrolysis-oxidation-phosphorization method. The obtained CoP/PNC exhibits promising electrocatalytic performance toward HER and OER due to the synergistic effect between N-doped carbon and CoP nanocrystals. When the CoP/PNC catalyst is applied in a two-electrode water splitting device, the cell potential at 10 mA cm−2 could be as low as 1.68 V. Besides, it still remains current retention of 78.7% after continuous run for 24 h.Graphical abstractImage 1
  • One-step growth of reduced graphene oxide on arbitrary substrates
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Mingguang Chen, Emre Yengel, Junwei Zhang, Chenxu Zhu, Xin He, Chenhui Zhang, Jing-Kai Huang, Mohamed Nejib Hedhili, Thomas Anthopoulos, Xixiang Zhang Reduced graphene oxide (rGO) has inherited the outstanding electronic, optical, thermal and mechanical properties of graphene to a large extent, while maintaining sufficient chemically active sites. Therefore, it has attracted a great deal of research attention in the fields of energy storage, electronics, photonics, catalysis, environmental engineering, etc. Currently, the most popular way to prepare rGO is to reduce graphene oxide, which is obtained by modified Hummer methods using tedious treatments in a harsh environment, to rGO flakes. Industrial applications demand advanced preparation methods that can mass produce highly uniform rGO sheets on arbitrary substrates. In this work, a one-step growth process is introduced that utilizes cellulose acetate as a precursor, without any catalysts, to produce uniform ultrathin rGO films on various substrates and free-standing rGO powders. Systematic spectroscopic and microscopic studies on the resulting rGO are performed. Prototypes of electronic and optoelectronic devices, such as field effect transistors (FETs), photodetectors, and humidity sensors, are fabricated and tested, demonstrating the intriguing applications of our rGO materials across a wide range of fields.Graphical abstractImage 1
  • Ultrathin multifunctional carbon/glass fiber reinforced lossy lattice
           metastructure for integrated design of broadband microwave absorption and
           effective load bearing
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yixing Huang, Xujin Yuan, Mingji Chen, Wei-Li Song, Jin Chen, Qunfu Fan, Liqun Tang, Daining Fang Microwave absorbers as an effective way to reduce microwave radiation in stealth technologies and electromagnetic compatibility have attracted great attentions recently. Herein, a novel multifunctional carbon fiber (CF)/glass fiber (GF) reinforced lossy lattice metastructure for broadband microwave absorption and effective load bearing is proposed for the first time based on the structural similarity of photonic crystal and lightweight mechanical lattice. The lossy lattice is fabricated with nano lossy composite composed of multiwall carbon nanotube (MWCNT) and spherical carbonyl iron (CI) particles to manipulate complex permittivity and complex permeability. Sub-wavelength effect and structural optimization are applied for the metastructure to extend −10 dB absorption bandwidth from 3.42 GHz to 19.73 GHz with thickness of 3.5 mm. With solid attachment of CF and GF, the metastructure achieves high average equivalent strength of 167.35 MPa and fracture strain of 5.45%. A long plastic stage of the metastructure is observed after GF fracture or GF delamination in three-point flexural test. The integrated design of microwave absorbing and mechanical properties make it promising for practical applications in mass production.Graphical abstractDielectric-magnetic lossy lattice metastructure composed of carbonyl iron and multiwall carbon nanotube is fabricated with a four-step method. Broadband absorption from 3.42 GHz to 19.73 GHz with thickness of 3.5 mm and large tensile strength of 167.35 MPa with fracture strain of 5.45% are achieved. Integrated design shed light on practical applications and mass production in stealthy technologies and lightweight armor.Image 102
  • Effects of ultraviolet irradiation on stabilization of textile-grade
           polyacrylonitrile fibers without photo-initiator for preparing carbon
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): A. Young Jo, Seung Hwa Yoo, Yong-Sik Chung, Sungho Lee The ultraviolet (UV) was irradiated on textile-grade polyacrylonitrile (PAN) fibers without photo-initiators to demonstrate the effective stabilization for preparing carbon fibers (CFs). The irradiation for as short as 20 min at 75 °C generated radicals in the textile-grade PAN fibers, which accelerate stabilization, resulting in significant reduction of process time. In addition, stepwise irradiations from 75 to 200 °C by increasing UV power, and following thermal treatments to mimic continuous stabilization for 30 min total provided CFs with tensile strength and modulus of 2.43 ± 0.4 and 195 ± 8.6 GPa. Considering conventional thermal stabilization for at least 60 min and 5 h with special and textile PAN fibers, respectively, the incorporation of UV irradiation into the present system could effectively advance stabilization process to shorten duration and to produce low-cost CFs based on textile-grade PAN fibers as one of cheap precursors.Graphical abstractImage 1
  • Lightweight, three-dimensional carbon Nanotube@TiO2 sponge with enhanced
           microwave absorption performance
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Zichao Mo, Rongliang Yang, Dongwei Lu, Leilei Yang, Qingmei Hu, Hongbian Li, Hai Zhu, Zikang Tang, Xuchun Gui Porous, spongy absorbers are considered to be the most promising candidates for lightweight and highly efficient microwave absorption material. However, conventional sponges or foams reported previously are difficult to meet the high performance requirements. Here, a lightweight (42 mg/cm3), porous CNT@TiO2 sponge with core-shell structure CNT/TiO2 was successfully prepared via a simple combination of hydrolysis and heat treatment method. In the sponge, the thickness and crystal structure of the TiO2 shell layer, and the mass fraction of TiO2 and CNTs can be precisely controlled by the growth processes, resulting in adjustable dielectric loss properties of the samples. With the optimized component proportion, it was found that a minimum reflection loss value of −31.8 dB was observed at 10.35 GHz, and reflection loss exceeds −10 dB is up to 2.76 GHz for the absorber with the thickness of 2 mm. Moreover, the effective microwave absorption (
  • Thermal and electrical transport properties in multi-walled carbon
           nanotube-coated ZnO tetrapods and self-entangled multi-walled carbon
           nanotube tubes
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Jan-Hendrik Pöhls, Fabian Schütt, Catherine O'Neill, Sindu Shree, Michel B. Johnson, Yogendra Kumar Mishra, Rainer Adelung, Mary Anne White We present the electrical and thermal properties of highly porous (∼94% porous) three-dimensional (3D) ZnO network structures coated with a thin layer of self-entangled multi-walled carbon nanotubes (MWCNTs), resulting in the formation of MWCNT microtubes (MWCNTTs) around the ceramic backbone. Additionally, we compare the properties of the composite (MWCNT/ZnO) structures to free-standing MWCNTTs, a hierarchical network consisting solely of randomly interconnected MWCNTs. The random 3D architecture of the ZnO network results in isotropic properties, in contrast to the typical one-dimensional (1D) properties of other CNT assemblies. The electrical conductivity of the MWCNT/ZnO composite increases with MWCNT content suggesting that MWCNTs are dominant over the entire temperature range. On the other hand, the thermal conductivity is mainly determined by the ceramic ZnO backbone at low temperature while the thermal conductivity of the MWCNTs is mainly dominant above 300 K. The electrical conductivity of the MWCNT/ZnO composites could reach values of up to 49 ± 2 S m−1 at room temperature whereas the room-temperature thermal conductivity of the MWCNTTs is 0.08 ± 0.02 W m−1 K−1. Direct comparison between both the composite and the pure MWCNTTs allows for a better understanding concerning which material in the composite dominates the transport properties.Graphical abstractImage 1
  • A way to improve the uniformity of nanometer-thickness graphite film
           synthesized on polycrystalline Ni substrate: From large grain to small
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Qicheng Hu, Seul-Gi Kim, Ki-Bong Nam, Jin-Ho Yeo, Tae-Sung Kim, Mun-Ja Kim, Ji-Beom Yoo A pellicle is an important part of mask protection in extreme ultraviolet (EUV) lithography, and nanometer-thickness graphite film (NGF) is an ideal material for pellicle fabrication. In our previous work, we synthesized large-scale NGF on polycrystalline Ni foil by a “two-stage” chemical vapor deposition process with an EUV transmittance of 79 ± 2%. The nonuniformity of EUV transmittance is mainly caused by the thicker NGF formed on the Ni grain boundaries (GBs). Here, we present a simple and cost-effective method to weaken the effects of the Ni GBs by sputtering thin Ni films onto Ni foils. The Ni film provides smaller grains with high GB density so that the non-uniformity of NGFs caused by Ni GBs was averaged out by the large EUV beam size. We investigated the grain growth of Ni films with different thicknesses, and 1-μm Ni film/Ni foil had the minimum average grain size of ∼6 μm. The NGF synthesized on it showed a higher EUV transmittance with better uniformity of 86.3 ± 0.9%. Fullerenic CC and sp3 CC bonding were detected by the X-ray photoelectron spectroscopy, and the NGF on the Ni GBs showed a higher defect density.Graphical abstractImage 1
  • Versatile reorganization of metal-polyphenol coordination on CNTs for
           dispersion, assembly, and transformation
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Jae Ho Kim, Jun Young Oh, Ye Eun Shin, Yo Chan Jeong, Taehoon Kim, Yeonsu Jung, Jin Seul Byun, Sae Jin Sung, Chong Rae Park, Seung Jae Yang Considerable researches have reported on the design of superstructured materials to exploit synergistic properties derived from building units. However, it is still limited to utilize superstructured materials in diverse ways by manipulating their characteristics and structures according to the required properties. This study presents a novel strategy for utilizing versatile reorganization of metal-polyphenol coordination to design multifunctional macroscopic superstructured materials based on carbon nanotubes (CNTs). The metal-polyphenol compounds surrounding the surface of CNTs adjust surface charges to overcome strong intermolecular van der Waals interaction, thereby forming stable aqueous dispersion. It is possible to assemble distinctive honeycomb-structured CNT aerogel from highly concentrated CNT suspension due to tiny 2D structured TA that connects the CNTs. Furthermore, metal ion and TA on the CNT network can be converted to metal oxide nanoparticle coated with thin carbon layer, which exhibits high potential as an anode material for lithium-ion battery.Graphical abstractImage 1
  • Analysis of the electro-optical response of graphene oxide dispersions
           under alternating fields
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Paloma Arenas-Guerrero, Ángel V. Delgado, María L. Jiménez Recently, graphene oxide (GO) has attracted much attention because of its many potential applications, such as the fabrication of transparent electrodes or drug delivery, in addition to its use as a precursor for large-scale production of graphene flakes. However, the interaction of this material with electric fields is yet poorly understood, and only recently the orientation of GO particles with an electric field was achieved. In this work, we analyse the electro-orientation of GO flakes in aqueous suspension in the absence of interparticle interactions, under different experimental conditions. From the measurement of linear dichroism, the electrical polarizability of the GO flakes as a function of the field frequency was calculated. The results show a pronounced relaxation process in the kHz range that leads to a large high-frequency polarizability. This phenomenology is explained as follows: For high-frequency fields, the polarizability is that of conducting particles immersed in a dielectric; for frequencies below the kHz range, in contrast, ions in solution redistribute and screen the induced dipole. Hence, the use of high-frequency electric fields strongly enhances GO electro-orientation. Furthermore, from the linear dichroism measurements, the particle absorption coefficient and the sample size distribution could be obtained.Graphical abstractImage 1
  • Carbon xerogels electrochemical oxidation and correlation with their
           physico-chemical properties
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Cinthia Alegre, David Sebastián, María J. Lázaro The electrochemical oxidation of carbon represents a relevant limitation for the application of carbon-based materials at the electrodes of several electrochemical devices, like fuel cells, metal-air batteries, water electrolyzers or supercapacitors. Understanding the key influencing parameters is thus of paramount importance to prevent and avoid the degradation of carbon materials. In the present investigation, carbon xerogels (CXGs) as a model of synthetic amorphous carbon, were studied on the basis of different surface chemistry and structure. Electro-oxidation experiments consisted of potential holding (1.2 V vs. RHE) on electrodes prepared with CXGs. The results indicate that the presence of oxygen groups (-C-O) and a higher ordering degree hinder the carbon oxidation reaction. A sub-structural parameter considering both the amount of oxygen-free carbon atoms (C-C + C*-C-O) from X-ray photoelectron spectroscopy, and the disordering degree from Raman spectra (in terms of ID/IG) is here proposed as a new factor to evaluate the tendency of an amorphous carbon material, like xerogels, to be electrochemically oxidized.Graphical abstractImage 1
  • Multiwall carbon nanotube encapsulated Co grown on vertically oriented
           graphene modified carbon cloth as bifunctional electrocatalysts for
           solid-state Zn-air battery
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yuanyuan Zhang, Haohao Sun, Yunfeng Qiu, Xinyang Ji, Tiange Ma, Feng Gao, Zhuo Ma, Baoxi Zhang, PingAn Hu Vertically-oriented graphene (VG) directly grown on carbon cloth serves as unique support for uniform growth of Zif-67 nanocrystals, and subsequent melamine-assisted pyrolysis results in the anchoring of multiwall carbon nanotubes (MWCNTs) encapsulated Co on VG. Systematic measurements indicate that pyridinic N and pyrrolitic N contents decreased from 600 to 900 °C, and the highest metallic Co contents, as well as well-defined MWCNTs were obtained at 800 °C. Taking advantage of the unique hierarchical nanostructures and adjusted compositions, the free-standing electrode shows excellent bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) activities. The presence of MWCNTs, metallic Co, active N species and Co-NxC sites, as well as in-situ formed Co oxides, will synergistically contribute to the electrocatalytic performance. Such free-standing film directly act as air-cathode to construct all solid-state Zn-air batteries (ZABs), showing comparable rechargeability to commercial Pt/C&Ir/C electrocatalysts, and also possessing unique flexibility. Present work opens a new avenue to improve the ORR and OER performance of Zif-67 derived nanomaterials via manipulating the hierarchical structure and chemical compositions, and sheds insights to the understanding of the electrocatalytic mechamism, also promotes the development of solid-state ZABs.Graphical abstractImage 1
  • Spin dependent resonant electron tunneling through planar graphene
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Shuanglong Liu, Yun-Peng Wang, James N. Fry, Hai-Ping Cheng We study spin-dependent electron transport properties of two dimensional graphene double and triple barrier junctions via first-principles calculations. The double barrier junction consists of two graphene leads, a quantum well of zigzag graphene nanoribbon (ZGNR) in the center, and two vacuum barriers separating the ZGNR from the two leads. Resonant electron tunneling occurs when the energy bands of graphene and ZGNR are well aligned in energy and wavevector. Highly spin-polarized electron transmission arises in such junctions when the two edges of the center ZGNR are in the ferromagnetic configuration. The spin polarization of the electron transmission at the Fermi energy can be tuned by gate voltage. We further investigate the dependence of the electron transmission on the width of the ZGNR, effects on barrier height when replacing vacuum by h-BN, and the consequence of replacing a double barrier by a triple barrier.Graphical abstractImage 1
  • Improving the tribological performance of epoxy coatings by the
           synergistic effect between dehydrated ethylenediamine modified graphene
           and polytetrafluoroethylene
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Bo Zhao, Tao Bai In this study, we exploited modified graphene and polytetrafluoroethylene (PTFE) to improve the tribological performance of epoxy coatings. The modified graphene (RGO-EDA) was obtained by reducing graphene oxide with dehydrated ethylenediamine to improve the dispersibility in epoxy resin (EP) and the interface bonding force between graphene and epoxy matrix. Different concentrations of RGO-EDA were added in the epoxy resin to produce the RGO-PTFE/EP composite coating and the tribological experiments were carried out. The tribological tests showed that the friction coefficient and wear rate of the epoxy coating were both significantly reduced after the addition of RGO-EDA and PTFE. The friction coefficient dropped from 1.121 to 0.139 and the wear rate reduced from 19.23 × 10−5 g min−1 to 15.21 × 10−5 g min−1 compared with neat epoxy coating when 1 wt% RGO-EDA and 10 wt% PTFE were added. The further study indicates the improvement in tribological performance of the composite coating is attributed to the excellent antifriction property of RGO-EDA and PTFE, the good dispersion of RGO-EDA in epoxy matrix and the high interface bonding force between RGO-EDA and epoxy matrix. At the end, a synergistic mechanism between RGO-EDA and PTFE is proposed to explain the improvement in tribological performance of epoxy coating.Graphical abstractImage 1
  • Designed synthesis of cobalt nanoparticles embedded carbon nanocages as
           bifunctional electrocatalysts for oxygen evolution and reduction
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Ya-Nan Hou, Zongbin Zhao, Han Zhang, Changtai Zhao, Xuguang Liu, Yongchao Tang, Zhanming Gao, Xuzhen Wang, Jieshan Qiu The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are fundamental for many renewable energy conversion and storage technologies. Developing economic and durable bifunctional ORR and OER electrocatalysts as substitute for noble-metal based catalysts, are urgently expected to reduce the industrial cost. Herein, a strategy towards synthesizing cobalt nanoparticles embedded N-doped carbon hollow nanocages (Co@NPC-H) by ion exchanging is reported. The Co@NPC-H nanocage structures integrate the high activity of heteroatoms doped catalytic active sites with the hollow structure for high exposure ratio of the active sites, exhibiting superior electroctalytic performance to noble-metal catalyst for both ORR and OER with the application potential of 860 mV when used as bifunctional catalyst, much smaller than other reported electrocatalysts, making Co@NPC-H a promising candidate as efficient air electrode in Zn-air batteries.Graphical abstractCobalt nanoparticles embedded carbon nanocages synthesized by the introduction of n-butylamine were applied as efficient electrocatalysts both for OER and ORR. The combination between Co bifunctional active sites and the hollow structure enables the increase of the oxygen electrode activity and demonstrates the superiority as cathode catalysts for Zn-air batteries.Image 1
  • Pilot-scale fabrication and analysis of graphene-nanocomposite fibers
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Benjamin A. Weise, Konstantin G. Wirth, Lukas Völkel, Markus Morgenstern, Gunnar Seide Graphene/polymer composites can be spun into fibers with remarkable mechanical, thermal and electrical properties, but few studies have considered requirements for the pilot-scale production of such fibers using commercially available graphene nanoplatelets (GnP). To address this limitation, we fabricated melt-spun polyamide 6 (PA6) multifilament yarns in which 3% or 5% (w/w) GnP was incorporated into the PA6 matrix by melt compounding during the initial process step. We tested a range of melt-spinning process parameters and analyzed the properties of the resulting fibers in detail. We were able to fabricate yarns containing 24 single filaments at a maximum winding speed of 1800 m/min while applying a draw ratio of 2.5. The electrical conductivity of the as-spun yarns was in the 10 μS/m range, which is suitable for the production of anti-static textiles. Furthermore, the degree of crystallization declined as the GnP content increased, reducing the tenacity of the yarn but improving its elastic modulus, allowing the production of composite textiles. In conclusion, we confirmed that large amounts of graphene can be incorporated into PA6 polymers by melt spinning and that the resulting composite fibers are suitable for multiple downstream applications in the textile industry.Graphical abstractImage 1
  • In situ measurement of rate-dependent strain/stress evolution and
           mechanism exploration in graphene electrodes during electrochemical
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Haimei Xie, Haibin Song, Jian-gang Guo, Yilan Kang, Wei Yang, Qian Zhang The micro-mechanical responses of an electrode dominate its electrochemical performance and lifetime. Herein, an experimental method is proposed to investigate the micro-strain/stress of graphene electrodes during galvanostatic charge/discharge cycling. The characteristic Raman peak of the graphene electrode is acquired in situ in a modified coin cell as a function of time. And two mechanical models are established, including microscale plane strain and plane stress with Li-induced-stiffening. Combining the mechanical models and the measured 2D peak, the micro-strain and micro-stress of the graphene electrode are quantitatively characterized. Furthermore, the deformation mechanism and rate-dependent characteristics are discussed. Excepting slight compressive loads by the solid–electrolyte interface film, the graphene experiences an increasing tensile strain/stress with increasing capacity. The stresses significantly depend on the charge/discharge rate, where higher stresses are induced at higher currents with a multiplicative relationship between the stress and current increments. The origins of the stress differences between macroscale and microscale involve the elongation of the intralayer C−C bonds caused by intercalated Li between the graphene layers and a microscopic concentration gradient. This work enhances the understanding of the microscopic mechano-electro-chemical mechanism of graphene electrodes and facilitates theoretical modeling of the stress with Li concentration and current.Graphical abstractImage 106365
  • Comparison of carbon materials as cathodes for the aluminium-ion battery
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): R.D. Mckerracher, A. Holland, A. Cruden, R.G.A. Wills Aluminium-ion batteries are of increasing interest as alternatives to lithium-ion batteries, as they use more abundant materials and suffer from fewer safety risks. The limiting factor for battery performance is the capacity of the cathode towards [AlCl4]- intercalation. Although several cathode materials have been used recently, there have been few studies that directly compare the capacity of different cathodes. Graphitic carbon materials have many features that make them ideal for aluminium-ion intercalation: they are electrically conductive, low density and low-cost, and are available in a wide variety of morphologies. This work compares four common forms of graphitic carbon: pyrolytic graphite, carbon paper, carbon cloth and carbon felt as aluminium-ion cathodes. The materials differ in their porosity, average graphite crystallite size, and properties as aluminium-intercalating agents. It was found that of all the materials examined, carbon paper had the highest energy density at 122−1, and had superior stability compared to pyrolytic graphite as the C-rate of cycling was increased. It also did not undergo crystallographic alteration even after cycling up to the 20C rate. Both carbon paper and pyrolytic graphite have capacities around 70 mAh.g−1 for aluminium intercalation, and carbon cloth and felt have lower capacities of 20–40 mAh.g−1.Graphical abstractSchematic Diagram showing operation principle of aluminium-ion battery (top right), with microstructure of cathodes (a) carbon cloth, (b) carbon paper, (c) carbon felt and (d) pyrolytic graphite (bottom right). The discharge capacity of materials (b) and (d) at varying current densities is shown on the left.Image 1043
  • How to overcome the electrical conductivity limitation of carbon nanotube
           yarns drawn from carbon nanotube arrays
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yoann Dini, Jérôme Faure-Vincent, Jean Dijon A complete literature review of carbon nanotube (CNT) yarn conductivities is presented, highlighting that CNT yarns made from CNT arrays grown by Chemical Vapor Deposition show a resistivity limitation of around 1 mΩ cm. We bring a deep understanding of the conduction limitation in CNT yarns spun from arrays thanks to systematic electrical transport studies in a large temperature range (3 K - 350 K) in CNT yarns made in different conditions of densification, doping and CNT lengths. The analysis of the electrical transport by the reduced activation energy clearly uncouples the effects of the inter-CNT contacts, prevailing below 70 K and the intrinsic CNT resistivity (prevailing above 70 K). Contrary to what is commonly accepted, we show that the contacts between CNTs have no impact on the CNT yarn resistivity at room temperature. In addition, we present a unique study of the structural and electrical properties of the CNT web which reveals that the CNT bundles are very well connected with each other. We estimate the CNT bundle resistivity (0.8 mΩ cm) to be close to that of the CNT yarn (1.1 mΩ cm). We conclude that, at room temperature, the CNT yarn resistivity is limited by that of the CNT bundle.Graphical abstractImage 1
  • Carbon-vanadium composites as non-precious catalysts for electro-reduction
           of oxygen
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Abdelhakim Elmouwahidi, Esther Bailón-García, Agustín F. Pérez-Cadenas, Jesica Castelo-Quibén, Francisco Carrasco-Marín A sol-gel synthesis method followed by carbonization is reported to obtain vanadium carbon composites. Samples are exhaustively characterized to correlate their chemical, textural and electrochemical properties with their behaviour as electro-catalysts for oxygen reduction reaction in a three-electrode electrochemical set-up in alkaline medium. The results show a very good electro-catalytic behaviour with large kinetic current densities (>20 mA/cm2) and low activation potentials (Eonset = −0.18 V and E1/2 = −0.24 V). The oxygen reduction reaction study of the catalysts shows that vanadium carbon composites possess a comparable catalytic performance to commercial Pt/C catalyst and that these composites offer a promising route for the activity enhancement of the non-precious metal catalysts.Graphical abstractClean and sustainable energy conversion systems are needed. Fuel cells are excellent candidates, but the high prize of ORR Pt-based catalysts limits its commercialization. VOx-C composites are good non-precious substitute catalysts with a catalytic performance comparable to commercial PtC electrodes.Image 1
  • O2+batteries&rft.title=Carbon&rft.issn=0008-6223&">Synthesis of Ag/Co@CoO NPs anchored within N-doped hierarchical porous
           hollow carbon nanofibers as a superior free-standing cathode for LiO2
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yuan Cao, Huimin Lu, Qingshui Hong, Binbin Xu, Junren Wang, Yan Deng, Wenwen Yang, Wei Cai To develop high-performance and efficient bifunctional electrocatalysts for LiO2 batteries, a promising new material is developed in this study, which consists of hierarchical porous hollow carbon nanofibers (HCNFs) with Ag/Co@CoO nanoparticles immobilized inside. This material is prepared using a facile and convenient coaxial electrospinning method, followed by a simple heat treatment. The Ag/Co@CoOHCNF cathode shows low polarization and excellent cycle performance. A combination of structural characterizations (e.g., scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman scattering spectroscopy, and the Brunauer-Emmett-Teller method) and electrochemical analyses shows that the excellent battery performance of the Ag/Co@CoOHCNF cathode can be attributed to its hierarchical porous structure, high surface area and high content of active sites combined with the synergetic interactions between Ag and Co@CoO as well as the improved electrical conductivity. Notably, the introduction of Ag may promote the Li2O2 to grow and crystallize into nanosheets due to the synergetic interactions between Ag and CoO. The petal-like Li2O2 discharge products formed on the Ag/Co@CoOHCNF cathode are more readily decomposed than the film-like Li2O2. Our findings provide a reference for designing free-standing high-performance hollow-structured Ag/Co@CoO hybrid electrodes by coaxial electrospinning for non-aqueous LiO2 batteries.Graphical abstractImage 1
  • Expanding graphene properties by a simple S-doping methodology based on
           cold CS2 plasma
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): V.K. Abdelkader-Fernández, M. Domingo-García, F.J. López-Garzón, Diana M. Fernandes, Cristina Freire, Ma Dolores López de la Torre, M. Melguizo, Ma Luz Godino-Salido, Manuel Pérez-Mendoza For the first time, graphene has been successfully doped with sulfur via short exposition to CS2 microwave cold plasmas, avoiding high-temperature and time/chemicals-consuming treatments. Different S-doped samples were obtained by varying the duration of plasma treatments, reaching a remarkable 2.3 at % of S content after only 5 min of exposition. The S-doped graphenes present several sulfur containing moieties, among which thioether groups resulted to be predominant. These moieties are covalently bond to graphene layers and exhibit good thermal and water stability. In addition, unlike others more conventional methods, S-doping via CS2 plasmas do not damage the structural order of graphene. The influence of sulfur doping on the graphene properties has been assessed through two different tests: on one side, the capture of Pd2+ ions in aqueous solution, and on the other, the electrocatalytic activity towards the production of oxygen from water (OER process). In both cases, the performance of the pristine graphene was significantly enhanced with S-doping. In addition, the capture of Pd2+ allows the formation of sulfur-Pd nanoclusters supported on the graphene surface, which are very useful in electrochemical devices.Graphical abstractImage 1
  • Sulfur bridges between Co9S8 nanoparticles and carbon nanotubes enabling
           robust oxygen electrocatalysis
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Jialin Wang, Hui Liu, Yang Liu, Wenhang Wang, Qian Sun, Xiaobo Wang, Xinyu Zhao, Han Hu, Mingbo Wu Electrocatalytic active species, for example, metal sulfides, have been widely combined with carbon nanomaterials for enhanced performance because of the synergetic effect arising from the interaction between different components. However, the binding between metal sulfides and carbon nanomaterials, which plays a key role in determining their interaction, has not been clearly elucidated. Herein, we reported the sulfur bridges between sulfur-doped carbon nanotubes (S-CNTs) and Co9S8 nanoparticles and their significant effect on the practical electrochemical performance. Compared to the physically mixed composites, the one with sulfur bridges between CNTs and Co9S8 shows much better performance in terms of oxygen evolution (overpotential of 0.331 V at 10 mA cm−2) and oxygen reduction (half-wave potential of 0.810 V). Demonstrating that the sulfur bridges facilitate fast electron hopping from conductive support to active species, thus contributing to the outstanding electrochemical performance. Moreover, a rechargeable Zn-Air battery based on our electrocatalyst with strong sulfur bridges delivers an outstanding performance in terms of ORR and OER bifunctional performances. The clear understanding of the sulfur bridges between CNTs and Co9S8 is believed to shed substantial light on the development of other high-performance electrocatalysts.Graphical abstractImage 1
  • Polyacrylonitrile coupled graphite oxide film with improved heat
           dissipation ability
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Ke Wang, Mengxiong Li, Jiajia Zhang, Hongbin Lu Graphene film has potential to act as an excellent heat dissipation material. However, its thermal conductivity suffers from some limitations, including small graphene lateral sizes and low production efficiency from a practical viewpoint. To solve these issues, we propose an industrially viable protocol to synthesize homogeneously oxidized graphite oxide (GtO) with large lateral sizes and easy-purifying features. We employ polyacrylonitrile (PAN) as a coupling agent to repair the defects on GtO sheets and link these sheets together during the annealing treatment. The graphitized GtO/10%PAN film (g-GtO/10%PAN) shows excellent thermal and electrical properties, with an in-plane thermal conductivity of 1629.24 ± 43.88 W m−1 K−1 and an electrical conductivity of 9645.29 ± 199.44 S cm−1. Furthermore, it also exhibits outstanding flexibility; the original thermal conductivity can be maintained after 20,000 times bending. The g-GtO/10%PAN film offers an alternative to replace commercially used graphitized polyimide (PI) film. Our research provides a general method for the fabrication of high quality graphene film.Graphical abstractImage 1
  • Ultrahigh-temperature conversion of biomass to highly conductive graphitic
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Feng Jiang, Yonggang Yao, Bharath Natarajan, Chunpeng Yang, Tingting Gao, Hua Xie, Yilin Wang, Lisa Xu, Yukun Chen, Jeffrey Gilman, Lifeng Cui, Liangbing Hu Graphitic carbon has attracted tremendous research interest in recent years owing to its exceptional thermal and electrical properties that arise from the ordered sp2 hybridized carbon structure. Due to its high activation energy, graphitization is often energy- and chemical-intensive. In addition, the electrical conductivity of graphitized materials has always been limited by the presence of intrinsic defects. In this paper, we propose a new method to convert lignin-based biomass into highly crystalline graphitic carbon by a Joule heating process. The Joule heating utilizes the internal resistance of a reduced graphene oxide/lignin (rGO-lignin) carbon film to heat the sample to up to 2500 K within 1 h. The annealing of lignin at this high temperature is found to remove impurities and intrinsic defects, as well as to initiate the graphitization process. Amorphous lignin carbon can be converted into short-range ordered and graphitic carbon with an ultrahigh electrical conductivity of 4500 S/cm, significantly higher than the original 6.4 S/cm. The microstructure change underlying this high electrical conductivity was further probed through electron microscopy and chemical analysis. This highly crystalline, electrically conductive graphitized lignin-carbon is expected to be useful for numerous applications where high conductivity and corrosion resistance are desired.Graphical abstractImage 1
  • Non-covalent pre-organization of molecular precursors: A facile approach
           for engineering structures and activities of pyrolyzed
           Co-N-C electrocatalysts
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Hao Mei, Mengran Yang, Yanfei Shen, Fei He, Zhixin Zhou, Xinghua Chen, Yiran Yang, Songqin Liu, Yuanjian Zhang The efficient and low-cost platinum group metal (PGM)-free metal-nitrogen-carbon electrocatalysts (M-N-C) are potential alternatives for the oxygen reduction reaction (ORR) in artificial energy conversion devices. However, the solid-state reactions of M/C/N-containing precursors at high temperature was rather complicated, making the engineering of carbonization processes of M-N-C catalysts challenging and less explored. Herein, we report a way to modulate the pyrolysis processes of M-N-C by pre-organization of the molecular precursors via a simple solvation, in which, the simultaneous hydrogen bonding and coordination interactions played an important roles. It was revealed that the supramolecular precursors from different solvents had the same chemical compositions but quite different crystal structures. Accordingly, the pyrolysis processes were greatly altered, making the as-prepared Co-N-C exhibit distinct morphologies ranging from worm-nanotubes to bamboo-nanotubes and to porous nanosheets. The optimized Co-N-C showed competitive bifunctional electrocatalytic ORR and OER activities, which were further successfully applied to advance the rechargeable Zn–air batteries with excellent cycling stability over 600 h at a current density of 20 mA cm−2 and voltage gap (0.76 V). This work highlights the great potential of the pre-organization for the designing and selecting of precursors to engineer pyrolyzed M-N-C with higher electrocatalytic activities.Graphical abstractImage 1
  • Exploring the sandwich antibacterial membranes based on UiO-66/graphene
           oxide for forward osmosis performance
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Jia Pang, Zixi Kang, Rongming Wang, Ben Xu, Xinyu Nie, Lili Fan, Fuxin Zhang, Xinxin Du, Shou Feng, Daofeng Sun Forward osmosis (FO) is an emerging membrane process driven by the osmotic pressure gradient for freshwater production. Low water flux, reverse solute diffusion, and membrane biofouling are three major issues affecting the FO performances, and the membrane material is one of the keys to solve them. The graphene oxide (GO) membrane exhibits high water flux, indicating its promising potential for application in the field of water purification. However, precisely control of the pore size of the GO membranes is necessary for efficient ion sieving. In this work, the hydrophilic metal-organic framework (UiO-66) nanoparticles, as the microporous fillers, are intercalated into the GO layers to form ultrathin "sandwich" membranes for improving the FO performances. The incorporated UiO-66 introduces uniform and suitable nanochannels that can effectively allow water to permeate through, while hinder the solutes of Na+ ions. Furthermore, the GO layers form the matrix of nanometer-thick membranes possess the antimicrobial activity (bacteriostasis of 90%), which would prevent the biofouling. In the FO model, the UiO-66/GO membrane exhibits a water flux of 29.16 LMH, which was 270% higher than the pristine GO membrane, while the reverse solute diffusion was reduced by 83.5% (12.86 gMH).Graphical abstractBy the incorporation of UiO-66 into GO matrix, a sandwich membrane was obtained with highly improved FO performance compared with the pristine GO membrane.Image 1
  • Detection of gas molecule using C3N island single electron
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): S. Rani, S.J. Ray C3N is a recently discovered 2D layered material structurally similar to graphene, which has demonstrated immense prospect for future nanoelectronics. In this work, we have designed and investigated the operation and performance of a C3N island single electron transistor (SET) for the first time. Using First-principles based calculations, we investigated the effect of various molecular adsorptions on the electronic and conduction behaviour of the SET. C3N was found to be the perfect host material for capturing CO2. The charge stability diagram carries the signature of different molecules within the SET and their presence can be uniquely identified from various line scans and normalised differential conductance behaviour obtained from it. Our results suggest the usefulness of such nanoelectronic structures for sensing toxic gas molecules which can be operational over a wide temperature range with detection sensitivity upto a single molecular level.Graphical abstractTwo-dimensional layered materials have huge prospect in future nanoelectronics due to their superior electronic, transport, mechanical properties etc. C3N is a newly discovered 2D material, which has a graphene like structure, but presence of a band gap offers its usefulness in switching which has been demonstrated experimentally. In this work, for the first time, we have investigated the operation of a unique nanoelectronic device, single electronic transistor made of C3N layer. First-principles calculations reveal the superior adsorption capacity of this material towards toxic gas molecules like CO2, SO2, NO etc. We have proposed an efficient detection methodology of such gas molecules using SET as a sensor, which can distinguish the presence of such toxic molecules with a single molecular resolution.Image 1
  • Enhanced resolution of ultra micropore size determination of biochars and
           activated carbons by dual gas analysis using N2 and CO2 with 2D-NLDFT
           adsorption models
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Jacek Jagiello, Jeffrey Kenvin, Alain Celzard, Vanessa Fierro In this study, biochars obtained by either direct carbonization or hydrothermal treatment of corn stems were used as precursors of two series of activated carbons (ACs). The pore size distributions (PSDs) of biochars and ACs were evaluated from N2 and CO2 adsorption isotherms using models based on the two-dimensional version of the non-local density functional theory (2D-NLDFT). We showed that more detailed carbon PSDs might be obtained from simultaneous (dual) gas analysis of both N2 and CO2 isotherms than from single isotherms. The dual gas method showed a peak at about 0.4 nm which was not detected by the single N2 analysis. This fact is related to the restricted diffusion of N2 into very narrow micropores at low temperatures and pressures. By modifying the lower pore width limit wmin in the nitrogen model, we obtained an excellent fit of the dual model to both isotherms for all studied samples, which demonstrates the reliability and robustness of this refined method. Finally, we demonstrated that this approach would allow measuring N2 isotherms at relative pressures starting at about 0.001 rather than at 10−6, which would save time without losing resolution of the calculated PSD.Graphical abstractImage 1011
  • Structure stability of few-layer graphene under high electric field
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Shuai Tang, Yu Zhang, Ningsheng Xu, Peng Zhao, Runze Zhan, Jun Chen, Shaozhi Deng The stability of material structure is the key factor to determine its service capacity and lifetime. The structure evolution of vertical few-layer graphene (FLG) under high electric field was directly observed in situ TEM. The structure stability of FLG depends on its crystallinity and edge morphology. The vertical FLG without pinhole defects can sustain an electrostatic field beyond 58.5 V/nm. The vertical FLG with pinhole defects disintegrated from top to bottom due to field evaporation and the critical electrostatic field weaken to 17.4 V/nm. The vertical FLG with curly layer perpendicular to the electric field stretched and slid at the edge due to the layer sliding and the critical fracture electrostatic field of it was low to 7.5 V/nm which is an order of magnitudes small than that of the curly layer parallel to the electrostatic field of 24.7 V/nm. Those results were the first direct observation of the nano-structure evolution of FLG under high electric field. It helps to understand the deterioration mechanism of FLG under high electric field in free space and provides guidance for the high electric field applications such as field electron emitter and scanning tunneling microscopy.Graphical abstractImage 102959
  • Reduction degree regulated room-temperature terahertz direct detection
           based on fully suspended and low-temperature thermally reduced graphene
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yang Cao, Yajing Zhao, Yingxin Wang, Yue Zhang, Jianguo Wen, Ziran Zhao, Lianqing Zhu A series of fully-suspended reduced graphene oxide (RGO) room-temperature THz detectors were fabricated based on low-temperature (from 100 to 350 °C) thermally-reduced free-standing graphene oxide (GO) thin films. The suspended configuration results in a four-fold increase in responsivity and at least one order of magnitude increase in response speed compared to the substrate-supported detector. More importantly, the responsivity can be adjusted over a wide range from 10−2–102 mA W−1 and simultaneously the response speed can be adjusted on the order of tens of milliseconds by only tuning the reduction temperature of GO namely the reduction degree of GO. The regulation mechanism was revealed at the molecular level, i. e., the content of C=O functional group and the O/C ratio inside RGO, which are vary with the reduction degree of GO, are closely related to THz absorbance and electrical conductivity of RGO thin films, respectively. The experimental results demonstrated that the as high as possible content of C=O functional group and simultaneously a moderate O/C ratio can achieve optimal synergy between the THz absorption and electrical conductivity of the RGO thin films, thereby achieving an optimal THz detection performance.Graphical abstractImage 1
  • Nanoporous ruthenium and manganese oxide nanoparticles/reduced graphene
           oxide for high-energy symmetric supercapacitors
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): K.P. Annamalai, Xiaoshuang Zheng, Jianping Gao, Tianlu Chen, Yousheng Tao Clean and sustainable energy storage is of increasing demands due to uncontrolled fossil fuel depletion and rapid global economy growth. At the same time, low cost and environmental-friendly electrode materials are desirable to speed up industrial smart device fabrication. We constructed high-energy supercapacitor with the electrode of ruthenium and manganese oxide nanoparticles (RM NPs) loaded reduced graphene oxide (RGO). Simultaneous preparation of high capacitive metal oxide nanoparticles on graphene allows low chemical consumption, while favorable reaction temperature, short reaction time and simple methodology open a way for the production. Physico-chemical characterization was carried out to analyze the nanostructure and chemical composition of the nanocomposites. Experimental results highlighted: 2–10 nm oxide nanoparticles were uniformly decorated on 2D-nanosheets of RGO. RM NPs enlarged RGO inter layers, giving enriched micro- and meso-pores. While assembling the nanocomposites as symmetric supercapacitor electrodes in 0.5 M KOH, they delivered a high capacitance of 641 F g−1 and energy density of 22.26 Wh kg−1 and retain initial capacitance over 1000 cycles. The excellent performance and robust stability demonstrate that the metal oxide loaded graphene composites allow us to develop highly efficient and low cost metal-based supercapacitors.Graphical abstractNanoparticles are loaded in the graphene layers and synergies are gained for the whole nanocomposite to be highly stable and capacitive. Facile synthesis is beneficial to the production of the electrode materials. Minimum metal oxide loading strategies significantly reduce the cost of the composites, which is highly demanded for their potential applications.Image 1
  • Investigations on structure-dependent microwave absorption performance of
           nano-Fe3O4 coated carbon-based absorbers
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Na Li, Guiwen Huang, Hongmei Xiao, Qingping Feng, Shaoyun Fu It is reported the magnetic coating structure has a significant influence on their microwave absorption performance (MAP) for nano-Fe3O4-coated CNT. However, it is still uncertain which type of coating structure is favorable for Fe3O4-coated reduced graphene oxides (rGO) to enhance the MAP. In this work, nano-Fe3O4 compact-coated rGO (FCG) and Fe3O4 loose-coated rGO (FLG) are prepared firstly and their MAP have been investigated. A strong coating structure dependent effect is found and the FCG is proved to own much better MAP than FLG. Afterwards, the nano-Fe3O4 compact-coated CNT and rGO mixture (FCCG) are fabricated. It is shown that the MAP could reach as low as −42.9 dB, and the high coverage density of Fe3O4 nanoparticles plays important role on achieving this excellent property. Furthermore, in order to investigate the synergistic effects between CNT and rGO, FCCG with different mass ratios of CNT to rGO have been synthesized and optimized to maximize the effective complementarities between the dielectric loss and the magnetic loss to obtain high MAP. Results show the FCCG with 50 wt% rGO content achieves the best MAP, which can be attributed to the promoted consequent dielectric relaxation process and the magnetic loss induced by the increased multiple interface.Graphical abstractComposite with excellent MAP has been obtained guided by the proposed coating structure-property relationship for nano Fe3O4 coated carbon-based materials.Image 1
  • One-step laser direct writing of boron-doped electrolyte as
           all-solid-state microsupercapacitors
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Xuemei Mu, Jingwei Du, Yan Li, Hao Bai, Hao Zhao, Zhiming Wei, Baoyu Huang, Yingzhuo Sheng, Zhenxing Zhang, Erqing Xie High specific energy microsupercapacitor (MSC) as miniature all solid-state energy storage device has attracted wide interest due to its high energy and power density, long cycle life, integrability and high safety. Here, we designed and fabricated symmetric microsupercapacitors by one-step laser direct writing of boron-doped electrolytes (B-LE). The boron-doped PVA/H2SO4 electrolyte was carbonized into interdigitated cross-linked porous carbon fiber electrodes by high energy laser irradiation. These devices can deliver a high areal capacitance of 1.57 mF cm−2 (corresponding volumetric capacitance of 3.14 F cm−3) at the current density of 0.01 mA cm−2 with 5 wt% H3BO3 loading, much higher than the devices without boron doping (0.40 mF cm−2 at the same current density). Moreover, the fabricated devices display good cycling stability with a capacitance retention of 89.27% after 3000 charge-discharge cycles. These results suggest that the one-step direct laser writing to fabricate symmetric MSC has broad applications in high energy and power storage devices for miniaturized electronics.Graphical abstractImage 1
  • Molecular simulations of carbon allotropes in processes with creation and
           destruction of chemical bonds
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): E. Tangarife, R.I. Gonzalez, C. Cardenas, E.M. Bringa, F. Munoz The development of sophisticated interatomic potentials for classical molecular dynamics and Monte Carlo simulations has several advantages, but also some drawbacks. One of them is the increase in their complexity, which could lead to unphysical results when used beyond the scope for which they were intended. AIREBO and REBO2 [1, 2] are among the most popular potentials for carbon simulations and they employ an auxiliary function called the switching function. While this function develops unrealistic large forces in situations involving bond breaking, it exists for a good reason: to avoid a discontinuity of the potential energy. In this work we show that disabling or modifying carelessly the switching function, as it is often done, is not a good practice and must be avoided. There are some good alternatives developed in recent years, like the REBO2-scr potential [3] based on a modified bond breaking scheme. We also compare and discuss the use of several potentials for some carbon allotropes in situations of creation and destruction of chemical bonds.Graphical abstractImage 1
  • Two step floating catalyst chemical vapor deposition including in situ
           fabrication of catalyst nanoparticles and carbon nanotube forest growth
           with low impurity level
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Toshiya Kinoshita, Motoyuki Karita, Takayuki Nakano, Yoku Inoue Carbon nanotube (CNT) forest with very low concentration of metallic impurity particle was grown by a two-step floating-catalyst chemical vapor deposition (CVD) method. Fe catalyst nanoparticles were uniformly formed on the substrate by flowing ferrocene/ethanol mist generated by an ultrasonic nebulizer. Then, the growth of the CNT forest was followed by a thermal CVD process in an identical furnace with acetylene as a carbon source. The separated process of catalyst formation and CNT growth leads to no formation of impurity particles on the CNT surfaces with a lower impurity level of 0.8 wt%. The gas-phase flow of the catalyst solution enables precise control of catalyst formation including diameter, radius of curvature and areal density of catalyst particle for long and dense CNT forest. The CNT forest grown under optimum conditions had a spin capability because of its high areal density greater than 1 × 1011 cm−2.Graphical abstractImage 1
  • Is there chiral correlation between graphitic layers in double-wall carbon
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Maoshuai He, Ziwei Xu, Danhong Shang, Xiuyun Zhang, Hao Zhang, Dong Li, Hua Jiang, Esko Kauppinen, Feng Ding Because of the unique concentric structure, double-wall carbon nanotubes (DWNTs) possess fascinating properties which depend on the respective chirality of both the outer and the inner tubes. In this work, we study the chiral correlations of DWNTs synthesized by chemical vapor deposition on Fe nanoparticles. Contrary to some recent report, the distribution of chiral angle difference between inner and outer tubes in our work agrees with that calculated for all possible configurations. Remarkably, DWNTs with commensurate structures, i.e. outer and inner tubes have same chiral angles, are observed. The mechanism for the formation of DWNTs with approximately commensurate structures is discussed on the basis of layer by layer model. Furthermore, the interactional energies between the inner and outer walls are calculated to address the stability of different DWNT configurations. This work helps understand the growth mechanism of DWNTs and comprehend their structure stabilities with different configurations.Graphical abstractDouble-wall carbon nanotubes (DWNTs) synthesized by chemical vapor deposition show randomly distributed chiral angle differences between inner and outer tubes. The mechanism for the formation of DWNTs with approximately commensurate structures is discussed based on layer by layer model. The interactional energies between the inner and outer walls are calculated to address the stability of different DWNT configurations.Image 107177
  • Flexible and robust laser-induced graphene heaters photothermally scribed
           on bare polyimide substrates
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Marco R. Bobinger, Francisco J. Romero, Alfonso Salinas-Castillo, Markus Becherer, Paolo Lugli, Diego P. Morales, Noel Rodríguez, Almudena Rivadeneyra We demonstrate the feasibility of fabricating cost-effective and robust laser-induced graphene (LIG) flexible heaters with an innovative technique based on the photothermal production of graphene with a foam-like morphology. The produced devices are precisely defined on a bare polyimide substrate without the need of photomasks by employing a computer numerical control (CNC) driven laser diode. The electrical properties of the LIG-based heaters can be tailored by adjusting the laser power. The resulting conductive material exhibits electrical and chemical properties which are similar to the ones for graphene such as a negative temperature coefficient of −0.46 m°C−1 and a maximum operating temperature of around 400 °C. The developed heaters can outperform the existing emerging technologies showing a very rapid and stable response up to 225 °C with the extra features of flexibility, biocompatibility, and environmental friendliness.Graphical abstractIn this study, we present a novel CNC-based technique for fabricating laser induced graphene films on bare polyimide substrate. The conductive films are used for flexible thin-film heaters that show a high mechanical and thermal robustness.Image 1
  • Tuning the interfacial thermal conductance via the anisotropic elastic
           properties of graphite
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Zhiyong Wei, Fan Yang, Kedong Bi, Juekuan Yang, Yunfei Chen The effects of interatomic bonding strengths of graphite itself, in the in-plane (IP) and cross-plane (CP) direction, on the interfacial thermal conductance between graphite and substrate copper (Cu), are investigated by molecular dynamics simulations. It is found that the interfacial thermal conductance at the graphite/Cu interface monotonically decreases with respect to the increase of the IP bonding strength of graphite. However, the interfacial thermal conductance has a maximum with respect to the increase of the CP bonding strength of graphite. By extracting the acoustic iso-energy surfaces and phonon density of states of graphite under various bonding strength parameters, it is found that increasing the IP bonding strength decreases both the incident phonon group velocity component and average interfacial transmission coefficient. Increasing the CP bonding strength also decreases the incident phonon transmission coefficient. However, increasing the CP bonding strength increases the phonon group velocity component. To provide a practical method to enhance the interfacial thermal conductance, we compared the interfacial thermal conductance of porous graphite/Cu interface, which is higher than the graphite/Cu interface mainly due to the large reduction of the in-plane elasticity. This study provides important guidance in the active regulation of the interfacial thermal conductance between anisotropic materials and substrate.Graphical abstractThe interfacial thermal conductance between graphite and substrate copper shows a downward trend with increasing in-plane bonding strength of graphite, and a maximum with increasing cross-plane bonding strength of graphite.Image 1
  • Stretchable and durable conductive fabric for ultrahigh performance
           electromagnetic interference shielding
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Li-Chuan Jia, Ling Xu, Fang Ren, Peng-Gang Ren, Ding-Xiang Yan, Zhong-Ming Li Ultrahigh performance electromagnetic interference (EMI) shielding materials with an EMI shielding effectiveness (EMI SE) of above 90 dB at a tiny thickness are urgently needed due to the rapid development of high precision and sensitive electronic instruments. Herein, a highly electrically conductive fabric (ECF) was fabricated for ultrahigh performance EMI shielding by integrating silver nanowires (AgNWs) and conformal polyurethane (PU) layers on a carbon fiber fabric (CFF). The resultant ECF exhibited a very high electrical conductivity of 15390 S/m and an exceptional EMI SE of 106.0 dB at a thickness of only 0.36 mm. Importantly, the ultrahigh EMI SE was reliable in our ECF even undergoing long-term cycling deformations, with 83% retention after 100 stretching-release cycles (10% strain) and 97% retention after 5000 bending-release cycles (2.0 mm bending radius). The ECF also exhibited excellent resistance to ultrasonic treatment (60 min), peeling test (100 cycles), and strong acidic/alkaline solutions (PH = 2.0/12.0), indicating mechanical fastness and chemical durability. Our work demonstrates the facile development of an ultrahigh EMI shielding material with both mechanical and chemical durability, potentially suitable for high precision and sensitive electronic instruments even under harsh conditions.Graphical abstractImage 1
  • Fiber-shaped asymmetric supercapacitor exploiting rGO/Fe2O3 aerogel and
           electrodeposited MnOx nanosheets on carbon fibers
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Mara Serrapede, Amjid Rafique, Marco Fontana, Abderaouf Zine, Paola Rivolo, Stefano Bianco, Loubna Chetibi, Elena Tresso, Andrea Lamberti The growing interest in developing wearable energy storage devices requires the identification of suitable materials for the fabrication of their components. In this paper we report a new asymmetric fiber-shaped supercapacitor exploiting a composite of hematite and reduced graphene oxide aerogel obtained by a hydrothermal synthesis in presence of green extract as anode material and electrodeposited nanostructured MnOx as cathode. The three dimensional arrangement of the graphene flakes during the hydrothermal self-assembly process provides a highly conductive porous matrix with high surface area and, most importantly, a pores structure able to guarantee the rapid diffusion of the electrolyte ions and a fast electron transport. By simply modifying the hydrothermal recipe adding a dispersion of hematite nanoparticles, obtained using olive leaves extract as green surfactant, it is possible to obtain the decoration of the graphene network with the pseudocapacitive material. The resulting nanocomposite rGO/Fe2O3 aerogel exhibits excellent pseudocapacitive behaviour and it is used, in combination with MnOx nanostructured electrode, to fabricate a flexible fiber-shaped device exhibiting superior rate capability and bending stability. The use of a green surfactant during the synthesis opens up new avenues for the fabrication of environmentally friendly electrodes for wearable energy storage applications.Graphical abstractImage 1
  • Nanotextures from orthogonal graphene ribbons: Thermal stability
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yan Yang, Kun Cai, Jiao Shi, Yi Min Xie In the present paper, the thermal stability of the nanotextures formed from the same-sized weft and warp graphene ribbons were examined by molecular dynamics simulations. It was found that graphene ribbons existed in a nanotexture had relative sliding, rotating and bending movements at room temperature. Due to asynchronous motion, the initially parallel ribbons (either weft or warp ribbons) became curved and a part of neighboring ribbons were found to be attached together, consequently, the obtained nanotexture became wrinkled and lost its stability. Moreover, the wrinkle direction was aligned with one of the diagonals of the square nanotexture. It was noticed that nanotextures formed from zigzag ribbons were thermally shrunk at higher temperatures, whereas, the nanotextures obtained from armchair ribbons manifested thermal expansion properties. Furthermore, nanotextures formed from ribbons wider than 0.7 nm were thermally stability at room temperature.Graphical abstractImage 10115
  • Nanoindentation of thin graphdiyne films: Experiments and molecular
           dynamics simulation
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Kailu Xiao, Jiaofu Li, Xianqian Wu, Huibiao Liu, Chenguang Huang, Yuliang Li Graphdiyne possesses not only high strength but also excellent ductility, making it possible to be used in future high-performance protective structures. In this paper, the mechanical properties of graphdiyne were firstly measured by AFM experiments, and the failure behavior during low velocity perforation was also investigated by molecular dynamics (MD) simulations. Firstly, the elastic modulus was measured to be about 218.5 GPa by AFM experiments, which is about half of its ideal value due to various defects and the layer numbers of the synthesized graphdiyne film. Then, the nanoindentation processes of graphdiyne films were investigated by MD simulations, and the elastic modulus and strength were simulated to be about 489.04 GPa and 33.95 GPa, respectively. The failure behavior of the graphdiyne film was also studied in atomic level. Sequential broken of CC, CC and CC bonds and recombination of the broken bonds were observed to form a unique lathy crack. Furthermore, the effects of loading speed and indenter radius on the mechanical response of graphdiyne were investigated. A revised formula was developed for analyzing the mechanical properties of films in AFM experiments under various loading conditions.Graphical abstractImage 1
  • Extreme static compression of carbon to terapascal pressures
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Hao Wu, Xudong Luo, Libin Wen, Hong Sun, Changfeng Chen Recent reports of record-setting ultrahigh static pressures achieved in diamond anvil cells (DACs, 495 GPa) and double-stage DACs (ds-DACs, 1 TPa) raise fundamental questions about mechanical response of diamond and related carbon structures under extreme compression. Here we present results from a combined first-principles calculation and finite-element analysis that unveil the mechanisms responsible for the greatly enhanced compressive strengths of these carbon structures by lateral confining stresses concentrated near anvil tips, stemming from structural deformations in compressed DACs and further strengthened by additional confining pressures in ds-DACs. Our results indicate that diamond anvils oriented in the [001] direction with a flat culet diameter of 20 μm can sustain peak pressures above 500 GPa, vastly exceeding its pure compressive strength of about 200 GPa. Among nano-carbon structures with enhanced shear strengths by nano- or grain-boundaries, we find that nano-twinned diamond possesses the highest compressive strength, reaching 1 TPa in ds-DAC settings, in agreement with experimental observations. The present findings establish key benchmarks and expand the realm of understanding of diamond and related carbon structures under extreme loading conditions; these results offer crucial insights for rational design of advanced and novel DAC devices.Graphical abstractImage 1
  • An efficient medium to intercalate metals into graphite: LiCl-KCl molten
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Mélissa Fauchard, Sébastien Cahen, Mickaël Bolmont, Ghouti Medjahdi, Philippe Lagrange, Claire Hérold A new synthesis method using molten salts has been achieved allowing the intercalation of metals (e.g europium) into graphite. This method consists in dissolving various metals in a LiCl-KCl medium intended to be intercalated. In this work, many reactions are carried out by dissolving metals of first and second columns of the periodic table (Li, Na, K, Mg, Ca, Sr, Ba) in the molten salts before performing intercalation reactions for periods ranging from few minutes to several days and for temperatures included between 400 and 450 °C. The obtained compounds are then characterized by X-ray diffraction. Three different behaviors have been observed. With alkali metals, the obtained GIC is systematically LiC6 GIC. Magnesium leads to a sample of pure graphite remaining pristine. In case of alkaline earth metals, calcium, strontium and barium, the intercalation of the metal is systematically observed. The method presented in this paper reports for the first time the synthesis of a bulk SrC6 GIC. Finally, the intercalation mechanism using this medium has been deduced from these results and thanks to a study performed by ex situ X-ray diffraction in the case of the formation of the EuC6 GIC.Graphical abstractImage 1063
  • Carbon foam electromagnetic mm-wave absorption in reverberation chamber
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): R. Pastore, A. Delfini, D. Micheli, A. Vricella, M. Marchetti, F. Santoni, F. Piergentili The electromagnetic (EM) absorbing cross section (ACS) of carbon foams in the mm-wave frequency range 50–70 GHz is analyzed by means of a reverberation chamber (RC) set-up. Carbon foams are lightweight cellular materials which are believed to provide benefits in EM interference/compatibility (EMI/EMC) issues, due to their significant thermo-mechanical and electrical properties. With respect to usually employed microwave test set-up, the range of frequency investigated allows to analyze the details of the foam bulk structure using shorter wavelengths. Moreover, the RC method allows to study the EM interaction with materials by taking into account not a single wave propagation mode (like in transmission line methods) but rather an homogeneous and statistically random EM field propagation. A full analysis of the material behavior can be thus carried out, by reproducing conditions similar to what really happens within operational environments. The foam EM properties are related to specific structural parameters, such as apparent density, open porosity, cell size/shape and 3-D arrangement. Significant ACS values are appreciated in low density foams; further, a functional dependence between EM mm-wave absorption capability and foam inner morphology is revealed, thus promoting the employed microwave set-up as effective method for supporting the structural analysis of porous materials.Graphical abstractImage 1
  • The role of precursor modification on the production of graphite foam
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): James W. Klett A high-conductivity graphite foam developed at Oak Ridge National Laboratory (ORNL) exhibits properties indicative of highly graphitic structure. Similar to highly-ordered natural flake graphite, the foam exhibits a peak in thermal conductivity at temperatures approaching liquid nitrogen. This is due to its highly-aligned graphitic structure along the cell walls. This paper explores the manufacturing process to identify processing conditions that most affect the properties of the foam, such that the production of the foam can be easily tailored to different applications. This paper also examines processing conditions for the precursor's preparation as well as additives to the precursor (such as graphene) on the resulting foam structure and thermal properties. It was found that heat treating the precursor mesophase to increase melt viscosity and decrease off gassing during foaming decreased the thermal conductivity of the final foams, however, it resulted in smaller pores. Additions of graphene platelets decreases the thermal conductivity of the foams while simultaneously decreasing the pore size as well. These tradeoffs are evident and present the manufacturer options to tailor the foams.Graphical abstractImage 1
  • Molecular insights into multilayer 18-crown-6-like graphene nanopores for
           K+/Na+ separation: A molecular dynamics study
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yaojia Chen, Yudan Zhu, Yang Ruan, Nana Zhao, Wei Liu, Wei Zhuang, Xiaohua Lu Currently, 18-crown-6-like graphene nanopore has emerged and received much theoretical and experimental attention. Inspired by the multilayer oxygen-containing structure of the K+ channel (KcsA), we adopted molecular dynamics to investigate the selectivity of K+/Na+ for a series of multilayer 18-crown-6-like graphene nanopores. The results demonstrated that the nanopores of the multilayer graphene could facilitate the selectivity of K+/Na+ compared to the monolayer graphene. A proper combination of layer number and interlayer spacing could achieve a high selectivity. The spatial distribution of fluid molecules and ionic hydration microstructures indicated that the easier dehydration of K+ could lead to the more uniformity of K+ pathways in the central region of the nanopore and in turn be helpful in increasing the selectivity of K+. Meanwhile, the increased unsuitability for the pore wall oxygen atoms to compensate the partial dehydrated Na+ could enhance the resistance of Na+. These findings provide useful insights to the further design of 18-crown-6-like and other crown-ether-like graphene nanopore-based nanodevices as sensors and ion separators.Graphical abstractImage 1
  • High-mechanical-strength polyimide aerogels crosslinked with 4,
           4′-oxydianiline-functionalized carbon nanotubes
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Zhaoxian Zhu, Hongjun Yao, Jinxin Dong, Zhen Qian, Wei Dong, Donghui Long Polyimide (PI) aerogels are among the most promising organic aerogels as thermal insulation materials, but brittle compressive strength severely limits their practical applications. Herein, we develop a novel procedure to prepare lightweight and strong PI aerogels crosslinked with 4,4′-oxydianiline (ODA)-functionalized carbon nanotubes (CNTs). PI gels could be produced by cross-linking anhydride capped polyamic acid oligomers, followed by chemical imidizing. CNTs, treated through ODA functionalization, not only provide affinity with solvents, but also react with terminal anhydride groups of PAA to form strong covalent bonding with polymer chains. These modified CNTs could serve both as rigid crosslinker and linear reinforcement, which can effectively suppress the shrinkage of aerogels during preparation process. The obtained aerogels possess developed mesoporous structure with density as low as 0.107–0.121 g cm−3. The addition of only a small amount of CNTs could increase the mechanical properties of PI aerogels drastically, e.g. a 19-fold increase in Young's modulus and 15-fold increase in yield strength. The addition of CNTs could also improve thermal stability, with only a slight increase in thermal conductivity from 0.018 W m−1 K−1 to 0.023 W m−1 K−1 at room temperature. These high-mechanical-strength aerogels with high thermal stability and low thermal conductivity render them potential candidates for various aerospace applications.Graphical abstractWe develop a novel method towards the modification of CNTs by the introduction of -NH2 from ODA, which acts as a chemical cross-linker site for PI as show in Figure a. Figure b depicts the process followed for the synthesis of CNTs-PI aerogels. 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-oxidianiline (ODA) are chosen to prepare the linear poly(amic acid) (PAA), because their aromatic substituents hinder the rearrangement of the oligomer chains.Image 1
  • Tailoring physical properties of carbon nanotube threads during assembly
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Noe T. Alvarez, Peter Miller, Mark R. Haase, Rui Lobo, Rachit Malik, Vesselin Shanov Spinnable carbon nanotubes (CNTs) are useful formats for studying physical properties of CNT fiber assemblies in their pristine states. They are free of catalyst, uniform in length, with a comparatively narrow diameter distribution, and their assembly into thread does not require additional chemicals or solvents. Good quality drawable CNT arrays can be readily assembled into uniform diameter threads with great control over the number of CNTs incorporated into the thread assembly. This uniformity allows study the physical properties that result from changes that occur during thread formation. Here, we report trends of electrical resistivity and mechanical strength that resulted from alterations in their manufacturing parameters, allowing to change intrinsic physical properties of a material such as electrical resistivity. We correlate the electrical resistivity and mechanical strength as a function of diameter, density, and turns/meter. Understanding the effects of dry-spinning parameters will allow a better design of the physical properties of CNT threads for specific applications, such as strain or electrochemical sensors.Graphical abstractImage
  • Ferroelectric domain dynamics and stability in graphene oxide-P(VDF-TrFE)
           multilayer films for ultra-high-density memory application
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Yingxin Chen, Lei Zhang, Jiahao Liu, Xinli Lin, Weizhong Xu, Yifeng Yue, Qun-Dong Shen The rapid growth of miniaturized electronic devices has raised the demand for compact, flexible, wearable, and non-volatile memory units. However, integration into nanoelectronic devices requires a scaled-down data-storage component, but this often results in the deterioration of the ferroelectric switching performance. Herein, we demonstrate a simple and scalable fabrication of poly (vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] film with graphene oxide (GO) nanosheets. Using piezoresponse force microscopy (PFM), the storage features of this multilayer film were investigated, including establishment of two stable memory states, ferroelectric switching dynamics in the point-polarization and linear-polarization modes, and time and thermal stability of information storage. Remarkably, the GO-P(VDF-TrFE) film favored formation of low-temperature (LT) ferroelectric phase with much more ordered sequences of trans conformations relative to pristine P(VDF-TrFE) due to the presence of electrostatic interaction between GO nanosheets and CF dipoles of P(VDF-TrFE), thus affording improved ferroelectric properties. The GO-P(VDF-TrFE) film showed several excellent storage features, such as ultra-high density of more than 300 Gbits in−2, good writing & erasing repeatability, long data retention time, and elevated device operation temperature. In-depth understanding and utilization of the excellent non-volatile memory performance of this new GO-ferroelectric system will open new avenues for the next generation of nanoelectronic devices.Graphical abstractThe GO-P(VDF-TrFE) multilayer film showed several excellent storage features, such as a significant asymmetry in the nucleation and domain growth, ultra-high density of>300 Gbits in−2, good writing & erasing repeatability, long data retention time and elevated device operation temperature. These excellent properties were closed related that low-temperature (LT) ferroelectric phase with much more ordered sequences of trans conformations relative to pristine P(VDF-TrFE) were formed in the GO-P(VDF-TrFE) multilayer film.Image 1
  • Effects of multi-walled carbon nanotubes on metabolic function of the
           microbial community in riverine sediment contaminated with phenanthrene
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Biao Song, Ming Chen, Shujing Ye, Piao Xu, Guangming Zeng, Jilai Gong, Juan Li, Peng Zhang, Weicheng Cao The ecological risks of carbon nanotubes in the aquatic environment are of great concern. In this work, the effects of multi-walled carbon nanotubes (MWCNTs) on metabolic function of the microbial community in sediment contaminated with phenanthrene were investigated. The metabolic function was evaluated by Biolog ECO microplates a month later after MWCNTs of various dosages (0.5%, 1.0%, and 2.0%, w/w) were incorporated into the phenanthrene-contaminated sediment. The self-organizing map (SOM) algorithm and principal components analysis were used for data processing. The incorporation of 0.5% MWCNTs into the contaminated sediment significantly enhanced microbial activity (from 0.83 to 0.92, average well color development) and Shannon-Wiener diversity index (from 3.19 to 3.23) compared with the blank control. Clustering the microbial communities in different treatments on the trained SOM suggested that phenanthrene had a greater impact on the metabolic function of sediment microbial communities than MWCNTs in the experiments. The metabolic differences caused by MWCNTs were mainly reflected in the utilization of amino acids and polymers. The results of this study may contribute to evaluating the ecological risks of MWCNTs in the aquatic environment and developing the secure applications of MWCNTs.Graphical abstractImage 1
  • Nitrogen-doped graphitic carbons with encapsulated CoNi bimetallic
           nanoparticles as bifunctional electrocatalysts for rechargeable Zn–Air
    • Abstract: Publication date: April 2019Source: Carbon, Volume 144Author(s): Liu Yang, Di Wang, Yanlong Lv, Dapeng Cao Highly efficient and low-cost bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are greatly desirable for rechargeable metal-air batteries. Herein, we propose a useful strategy of integrating a bimetallic nanoparticle into the N-doped porous carbon to synthesize highly active bifunctional oxygen catalyst (CoNi/NG). The bimetallic CoNi/NG catalyst exhibits a positive half-wave potential of 0.85 V (versus, RHE) for ORR, and a low operating potential of 1.6 V (versus, RHE) to achieve a 10 mA cm−2 current density for OER. The excellent bifunctional properties of CoNi/NG are attributed to the various active sites (i.e., Co-N-C, Ni-N-C moieties and N-C sites) and its 2D graphene-like ultrathin structure, as well as synergistic effect of CoNi alloys. Importantly, the liquid Zn-air battery with CoNi/NG as oxygen electrode presents not only excellent charging and discharging curves and maximal power density of 130.5 mW cm−2, but also robust durability with only 50 mV increase in the voltage gap (the voltage difference between the charging and discharging) after continuous 110 h cycle tests. This work provides a general design principle for development of bifunctional catalysts by integrating different bimetals responsible for different electrochemical reactions into the N-doped graphitic carbons.Graphical abstractWe propose a universal design principle to develop bifunctional catalysts by integrating different metals beneficial for different electrochemical reactions into N-doped carbon nanosheets. The as-synthesized CoNi/NG-based Zn-air battery exhibits high power density and robust durability, which is greatly better than the Pt/C + IrO2-based counterpart.Image 1
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