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  Subjects -> CHEMISTRY (Total: 886 journals)
    - ANALYTICAL CHEMISTRY (55 journals)
    - CHEMISTRY (619 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (43 journals)
    - ORGANIC CHEMISTRY (49 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (619 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: 27)
ACS Catalysis     Hybrid Journal   (Followers: 44)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 22)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 26)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 41)
ACS Nano     Hybrid Journal   (Followers: 292)
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: 69)
Advances in Chemical Science     Open Access   (Followers: 18)
Advances in Chemistry     Open Access   (Followers: 22)
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: 26)
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: 18)
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  
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: 21)
American Journal of Chemistry     Open Access   (Followers: 31)
American Journal of Plant Physiology     Open Access   (Followers: 11)
American Mineralogist     Hybrid Journal   (Followers: 15)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 170)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 252)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 5)
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: 24)
Applied Surface Science     Hybrid Journal   (Followers: 32)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
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: 2)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Hybrid Journal   (Followers: 366)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 10)
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: 22)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 133)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 87)
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: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 70)
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: 10)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 74)
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: 196)
Chemical Science     Open Access   (Followers: 26)
Chemical Technology     Open Access   (Followers: 28)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 32)
Chemistry & Industry     Hybrid Journal   (Followers: 7)
Chemistry - A European Journal     Hybrid Journal   (Followers: 159)
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: 4)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Materials     Hybrid Journal   (Followers: 263)
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: 4)
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: 23)
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: 6)
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: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 6)
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: 71)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 3)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  

        1 2 3 4 | Last

Journal Cover
Carbon
Journal Prestige (SJR): 2.226
Citation Impact (citeScore): 7
Number of Followers: 70  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0008-6223
Published by Elsevier Homepage  [3162 journals]
  • Enhanced electromagnetic wave absorption of nanoporous Fe3O4 @ carbon
           composites derived from metal-organic frameworks
    • Abstract: Publication date: February 2019Source: Carbon, Volume 142Author(s): Zhen Xiang, Yiming Song, Juan Xiong, Zhongbin Pan, Xiao Wang, Lei Liu, Rui Liu, Huawei Yang, Wei Lu Electromagnetic wave absorbing materials have been widely applied in the wireless communication, electronic devices, and radar technology. In this work, metal-organic frameworks derived nanoporous Fe3O4 @ carbon (Fe3O4@NPC) composites were successfully obtained by a simple method. Electromagnetic wave absorbing performances were significantly enhanced due to the optimal impedance matching and strong attenuation via the synergy between the dielectric loss and the magnetic loss. As a result, the Fe3O4@NPC composites exhibited excellent electromagnetic wave absorbing properties, in which a strong reflection loss (RL) of −65.5 dB at 9.8 GHz as well as a wide absorbing bandwidth of 4.5 GHz (RL  
       
  • Boosting oxygen reduction catalysis with N, F, and S tri-doped porous
           graphene: Tertiary N-precursors regulates the constitutions of catalytic
           active sites
    • Abstract: Publication date: February 2019Source: Carbon, Volume 142Author(s): Yi Li, Hejing Wen, Juan Yang, Yazhou Zhou, Xiaonong Cheng Single or binary heteroatom-doped carbons, as excellent electrocatalysts towards oxygen reduction reaction (ORR), are widely investigated in recent years. However, due to difficulties in choosing suitable precursors, lacking of design principles, and controlling beneficial constitutions of heteroatoms, the development of ternary or multi-doped carbons still remains a great challenge. Herein, with N as the primary dopant, we also dope F and S atoms into graphene carbon matrix to offer promotional effect using a novel tertiary N-precursors inspired strategy. Composition and performance studies demonstrate that introducing the secondary and tertiary N-precursors could increase the configurations of active sites, thus improving the catalyst's ORR activity. Remarkably, after reaching further doping with F, S atoms, the obtained N, F, and S tri-doped porous graphene (FN3SG) shows greatly enhanced ORR performance with positive onset potential of 0.988 V and half-wave potential of 0.803 V vs. RHE comparable to the Pt/C in alkaline media, which is mainly attributed to its more introduced active sites and porous architectures. Furthermore, the as-prepared FN3SG catalyst also exhibits better methanol tolerance and higher stability. This facile but general synthesis strategy can be extended to design and prepare of other carbon-based electrocatalysts with high-performance catalytic activities.Graphical abstractImage 1
       
  • N-doped graphene /carbon hybrid aerogels for efficient solar steam
           generation
    • Abstract: Publication date: February 2019Source: Carbon, Volume 142Author(s): Bingbing Huo, Degang Jiang, Xueying Cao, Hui Liang, Zhen Liu, Chenwei Li, Jingquan Liu Efficient solar-thermal energy conversion is critical for utilization of abundant solar energy in solar power-based concentration systems, photochemical plants and seawater desalination technologies, etc. However, conventional processes for solar steam generation generally rely on high-temperature heating of bulk liquids, which requires highly concentrated solar energy and suffers from high energy and optical losses. Therefore, it is still critical to explore and design solar absorption materials with high solar-thermal conversion efficiency. Herein, we report the preparation of a nitrogen-doped graphene/carbon hybrid aerogel (NGCA) using graphene oxide (GO) and melamine form (MF) for highly efficient solar steam generation by a simple dip-coating processes, air drying and carbonization at different temperatures. The NGCA carbonized at 600 °C (NGCA-600) exhibits excellent stability, efficient light absorption, good hydrophilicity for water supply and abundant micro-pores for vapor escape, therefore, it can achieve 90% solar-thermal conversion efficiency under the light density of 1 kW m−2. This cost-effective and reusable solar-thermal convertible material could be ideal for practical applications in seawater desalination, water purification and sterilization.Graphical abstractA 3D nitrogen-doped graphene/carbon hybrid aerogel (NGCA) using melamine foam (MF) as skeleton is fabricated through a simple dip-coating process, air-drying and thermal-treatment, and utilized as an attractive material for efficient steam generation.Image 1
       
  • Fast synthesis of thin graphite film with high-performance thermal and
           electrical properties grown by plasma CVD using polycrystalline nickel
           foil at low temperature
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Ryuichi Kato, Masataka Hasegawa We have developed a high speed, low temperature synthesis method of thin graphite film by plasma-enhanced chemical vapor deposition (plasma CVD). The synthesis time was less than 60 min and the highest process temperature was 1300 °C. Raman spectroscopy, X-ray diffraction and cross-sectional transmission electron microscopy (TEM) show a high crystallinity of synthesized graphite film. The graphitization of the film was larger than 0.944, which suggests that the film was nearly completely graphitized. The thermal conductivity of the film was 1570 W/mK which is the highest among of graphite synthesized by CVD on transition metal substrates.Graphical abstractImage
       
  • Organophosphorus-based polymer covalently functionalized reduced graphene
           oxide: In-situ synthesis and nonvolatile memory effect
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Yaming Cao, Yubin Fu, Dongqi Li, Chunxuan Zhu, Bin Zhang, Yu Chen The best strategy to improve the solubility of two-dimensional materials is merge them into a polymer backbone or a polymer matrix to form new kind of functional materials. A novel π-conjugated and highly soluble organophosphorus-based polymer covalently functionalized reduced graphene oxide derivative material, PTPEB-g-RGO, has been successfully synthesized, characterized, and was used as active layer material in resistive random access memory (RRAM) devices. The as-fabricated Al/PTPEB-g-RGO/ITO device exhibited nonvolatile bistable resistive switching performances with a large ON/OFF current ratio surpassing 104, long retention time over 104 s, excellent endurance over 200 switching cycles, significant slight ΔON-OFF value and remarkable repeated “write-read-erase-read-rewrite” capability. A slight value difference between the turn on voltage and turn off voltage is beneficial for reducing power consumption and decreasing information misreading rate in digital memory cell. The present research work offers a significant insight for the future development of organic memory devices by taking advantage of organophosphorus-based polymer material.Graphical abstractImage
       
  • Crab shell derived multi-hierarchical carbon materials as a typical
           recycling of waste for high performance supercapacitors
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Min Fu, Wei Chen, Xixi Zhu, Baochan Yang, Qingyun Liu The exhausting energy forces us to search for new green energy and develop energy storage and conversion technologies. Supercapacitors with long service life and high power density show broad application prospect. The multi-hierarchical porous carbon materials were prepared using the crab shell, a typical seafood waste, as the precursor, and investigated as supercapacitor electrode materials. The crab shell derived carbon exhibited specific capacitances of 322.5 and 223.4 F g−1 at current densities of 1 and 10 A g−1 respectively, indicating good capacitive performance and rate capability. Additionally, its cyclic performance was impressive with less than 1% capacitance fading over 10000 cycles at 1 A g−1. The crab shell derived carbon were further used as support to assemble SrFe12O19 for constructing a superior hybrid supercapacitor with the specific capacitance of 690.4 F g−1 at 1 A g−1, and 401.3 F g−1 even at 10 A g−1. Furthermore, the crab shell derived carbon/SrFe12O19 composites displayed the exceptional cycling performance over 10000 cycles with 94.5% of capacitance retention, indicating distinguished capacitive performances. Such cheap, green and high-performance electrode composites based on crab shell waste provide good prospects in energy storage applications.Graphical abstractThe synthesis of crab shell based multi-hierarchical porous carbon as advanced electrode materials for supercapacitors.Image 1
       
  • Superior corrosion resistance and self-healable epoxy coating pigmented
           with silanzied trianiline-intercalated graphene
    • Abstract: Publication date: Available online 17 October 2018Source: CarbonAuthor(s): Yuwei Ye, Dawei Zhang, Tong Liu, Zhiyong Liu, Jibin Pu, Wei Liu, Haichao Zhao, Xiaogang Li, Liping Wang In this study, novel aniline trimer (AT) functionalized graphene sheets (SAT-G) was prepared by intercalation and silanization of trianiline precursor. Fourier transform infrared spectroscopy (FTIR), Raman and UV-vis spectra indicated that the π-π interaction was formed between the silanized aniline trimer (SAT) and graphene (G). Meanwhile, scanning electron microscope (SEM), transmission electron microscope (TEM), and scanning probe microscope (SPM) confirmed the successful decoration of graphene surface by AT. As a result, the silanized aniline trimer could effectively increase the dispersion of graphene in epoxy matrix. The long-term anti-corrosion ability of epoxy matrix was greatly enhanced via adding proper SAT-G (0.5 wt%). Local electrochemical impedance spectroscopy (LEIS) studies manifested that the local impedance of artificial defect was greatly improved. The excellent anti-corrosion performance was attributed to two parts: (1) the well-dispersion graphene could fully exhibit its barrier property; (2) the silanized aniline trimer with intact electroactivity could induce the formation of passive film, which was composed by Fe3O4 and Fe2O3. The combine action between the barrier property of graphene and the self-healing capacity of silanized aniline trimer contributed to the superior corrosion resistance of SAT-G based epoxy coating.Graphical abstractImage 1
       
  • PtCo bimetallic nanoparticles encapsulated in N-doped carbon nanorod
           arrays for efficient electrocatalysis
    • Abstract: Publication date: Available online 17 October 2018Source: CarbonAuthor(s): Weina Ren, Wenjie Zang, Haifeng Zhang, Jialin Bian, Zuofeng Chen, Cao Guan, Chuanwei Cheng Highly-active and durable electrocatalysts are highly important for electrochemical energy conversion devices. Herein, we report the design and fabrication of PtCo bimetallic nanoparticles encapsulated in N-doped carbon nanorod arrays (PtCo@NC) on carbon cloth as an integrated binder-free catalyst for both methanol oxidation oxidation (MOR) and hydrogen evolution reaction (HER). The unique structural advantage and bimetallic synergetic effect of such composite catalyst provide a high specific surface area and abundant electrochemical active sites for the electrocatalysis process. As a result, the as-obtained PtCo@NC with optimized Pt loading exhibit significantly improved methanol electro-oxidation performance in terms of high areal activity of 2.17 mA cm−2, superior CO tolerance and reliable stability in contrast to that of commercial Pt/C catalysts. In addition, the PtCo@NC catalyst also shows promising electrocatalytic activity with small onset potential of 12 mV vs RHE, low Tafel slope of 48 mV dec−1 as well as excellent long-term stability for HER.Graphical abstractImage 1
       
  • Corrigendum to “Tribochemistry of graphene on iron and its possible role
           in lubrication of steel” [Carbon 106 (2016) 118–124]
    • Abstract: Publication date: Available online 17 October 2018Source: CarbonAuthor(s): Paolo Restuccia, M.C. Righi
       
  • Robust micropatterns on graphene oxide films based on the modification of
           fluorescence lifetime for multimode optical recording
    • Abstract: Publication date: Available online 17 October 2018Source: CarbonAuthor(s): Zhixing Qiao, Chengbing Qin, Wenjun He, Yani Gong, Bin Li, Guofeng Zhang, Ruiyun Chen, Yan Gao, Liantuan Xiao, Suotang Jia Here we report on the fine modification of fluorescence lifetime of graphene oxide (GO) film by introducing a localized writing process with a well-controlled reduction degree. The modification results from the elimination of long-lived sp3 functional groups and/or the conversion of that to short-lived sp2 confined clusters. By optimizing the parameters of writing process, four-lifetime distributions with narrow width have been determined. The distinguishable lifetime distributions allow to create versatile and complex micropatterns on the GO film, which are robust with film-thickness- and reading-power-independent features. These features enable a multimode optical recording on GO film for high-capacity information storage based on the contrast of fluorescence lifetime. Our results present that lifetime modification of GO film can provide a new platform for the fabrication of micro-photonic information devices.Graphical abstractImage 1
       
  • Vacancy-controlled friction on 2D materials: Roughness, flexibility, and
           chemical reaction
    • Abstract: Publication date: Available online 16 October 2018Source: CarbonAuthor(s): Jun Liu, Yizhou Qi, Qunyang Li, Tianying Duan, Wen Yue, Ajay Vadakkepatt, Chang Ye, Yalin Dong It was recently reported that the presence of vacancy could dramatically increase nanoscale friction of graphene, while its underlying mechanism remains unknown [1]. In this study, molecular dynamics simulation is carried out to examine the possible mechanisms that could contribute to friction enhancement on chemically modified and/or vacancy-contained graphene. It is found that the changes in out-of-plane flexibility due to vacancies had only a limited influence on friction. In contrast, the Schwoebel barrier, the chemical reactivity of dangling bonds at the atomic step edges, as well as the roughening induced by functional groups can contribute more to nanoscale friction of graphene. This study provides a friction-mechanism map that correlates frictional behavior to various atomic scale mechanisms, which is useful for understanding the nanoscale friction of defected graphene.Graphical abstractImage 1
       
  • Highly conductive doped carbon framework as binder-free cathode for hybrid
           Li-O2 battery
    • Abstract: Publication date: Available online 16 October 2018Source: CarbonAuthor(s): Juan Nong, Pu Xie, Ao Sheng Zhu, Min Zhi Rong, Ming Qiu Zhang Nitrogen doped carbon materials have been found to be a capable oxygen electrocatalyst for low-cost and highly durable metal-oxygen batteries. However, it is still a challenge to associate the precise working mechanism with their molecular structure, specific surface area and conductivity. By using first-principles calculations and experimental studies, for the first time, we clarify the higher catalyst activity of pyridinic-N than graphitic-N in highly conductive and porous carbon framework. Accordingly, an ultrahigh conductive three-dimensional doped carbon framework that consists of networked and hollow pipelines with nanometer-thick walls is prepared. Benefiting from such a unique structure, the as-made carbon framework as binder-free cathode for hybrid Li-O2 battery delivers 150 cycles at 1 A g−1 on deep (dis)charge. More importantly, based on the total mass of pyridinic nitrogen doped carbon framework, the capacity of the Li-O2 battery containing the binder-free carbon framework cathode amounts to 49.5 Ah g−1.Graphical abstractCatalytic activity of pyridinic-N of carbon framework can be improved by enhancing electron mobility and transport paths, and decreasing electron scattering interfaces, as proved by first-principles calculations and experimental studies. Accordingly, a three-dimensional N-doped carbon framework is fabricated via morphology-controlled solid-state pyrolysis of polyaniline foam, which successfully acts as a low-cost and highly catalytic active binder-free air cathode for hybrid electrolyte lithium-oxygen battery.Image 1
       
  • Bottom-up synthesis and structural design strategy for graphene quantum
           dots with tunable emission to near infrared region
    • Abstract: Publication date: Available online 16 October 2018Source: CarbonAuthor(s): Dapeng Huang, Haifeng Zhou, Yaqiang Wu, Tao Wang, Leilei Sun, Peng Gao, Yuzhen Sun, Huining Huang, Guangjun Zhou, Jifan Hu Despite recent advances in the fabrication of graphene quantum dots (GQDs) with excellent fluorescence performance, it has been challenging to extend the fluorescence emission to deep red and short wave near-infrared. Herein, we present a strategy to reach the goal via hydrothermal treatment of polythiophene derivatives which mainly comprises a polythiophene conjugate skeleton, lots of benzene ring structure and alkyl chain. This structure is thermally converted into a doped crystalline GQDs at 170 °C for 20 h with the maximum fluorescence emission at 700 nm. In addition, the length of alkyl chain also has a regulatory effect on emission wavelength of final products, which enables the chemical molecular-level structural design of GQDs with specific light emission waveband.Graphical abstractImage 1
       
  • Field emission properties of edge-functionalized graphene
    • Abstract: Publication date: Available online 16 October 2018Source: CarbonAuthor(s): Yanlin Gao, Susumu Okada A comprehensive study on electrostatic potential properties of edge-functionalized graphene under an external electric field was performed by using the density functional theory. The shapes and attached functional groups of the edges cause substantial variation of their electrostatic potential outside the edges. Our calculations reveal that graphene edges functionalized by H, OH, and COOH cause relatively large emission current for a wide range of the electric field due to the decrease in the potential barriers caused by the dipoles compared to that before functionalization, while an O termination substantially suppresses the current by increasing the potential barrier. In addition, the NH group increases and decreases the field emission current from zigzag and armchair edges, respectively, because of the different electrostatic environment around the edge atomic sites arising from the NH group conformations.Graphical abstractImage 1
       
  • Solution-processed Graphene-MoS2 heterostructure for efficient hole
           extraction in organic solar cells
    • Abstract: Publication date: Available online 16 October 2018Source: CarbonAuthor(s): Xuan Zheng, Huijun Zhang, Quanling Yang, Chuanxi Xiong, Wei Li, Yu Yan, Robert S. Gurney, Tao Wang A major bottleneck exploiting the unique electronic properties of two-dimensional materials like graphene is the lack of mass production methods that are able to produce van der Waals heterostructures. Here, we prepare Graphene-molybdenum disulfide (MoS2) heterostructures via liquid-phase exfoliation followed by hydrothermal reaction, and employ Graphene-MoS2 hybrid thin films as the hole extraction layer in PTB7-Th:PC71BM organic solar cells. We demonstrate a maximum power conversion efficiency of 9.5% whilst retaining more than 93% of the initial efficiency over a storage period of 1000 h, surpassing current reported two-dimensional materials based devices. Our results represent the great potential of two-dimensional heterostructures as hole extraction materials for efficient and stable photovoltaics devices.Graphical abstractImage 1
       
  • Image based in silico characterisation of the effective thermal properties
           of a graphite foam
    • Abstract: Publication date: Available online 14 October 2018Source: CarbonAuthor(s): LlM. Evans, L. Margetts, P.D. Lee, C.A.M. Butler, E. Surrey Functional materials' properties are influenced by microstructures which can be changed during manufacturing. A technique is presented which digitises graphite foam via X-ray tomography and converts it into image-based models to determine properties in silico. By simulating a laser flash analysis its effective thermal conductivity is predicted. Results show ∼1% error in the direction the foam was ‘grown’ during manufacturing but is significantly less accurate in plane due to effective thermal conductivity resulting from both the foam's microstructure and graphite's crystalline structure. An empirical relationship is found linking these by using a law of mixtures. A case study is presented demonstrating the technique's use to simulate a heat exchanger component containing graphite foam with micro-scale accuracy using literature material properties for solid graphite. Compared against conventional finite element modelling there is no requirement to firstly experimentally measure the foam's effective bulk properties. Additionally, improved local accuracy is achieved due to exact location of contact between the foam and other parts of the component. This capability will be of interest in design and manufacture of components using graphite materials. The software used was developed by the authors and is open source for others to undertake similar studies.Graphical abstractImage 1
       
  • Initial stages of graphene oxide cracking in basic media
    • Abstract: Publication date: Available online 13 October 2018Source: CarbonAuthor(s): M. Dionizio Moreira, V.R. Coluci Despite the increasing interest in graphene oxide (GO) and its properties, currently there is no consensus on its structure. In the recently proposed two-component model, the GO structure consists of slightly oxidized graphene sheets and small organic molecules physisorbed on them. The formation of these molecules has been later attributed to the GO rupture caused by basic treatment under heating. In this work, we studied the initial stages of the GO rupture in hydroxyl chains by using first principles electronic calculations. Possible routes to cracking originated from different configurations of hydroxyl chains and under possible reactions in basic media were analyzed. Resulting from successive hydroxide ion attacks, cracks were observed for chains with hydroxyls arranged in armchair and zigzag configurations. Bond breaking due to the presence of ketones located at opposite sides of the basal plane was shown to play a role on cracking initiation and propagation. Cracking driven by structural deformations was also observed for chains comprised of parallelly orientated vicinal diols.Graphical abstractImage 1
       
  • Bundled and dispersed carbon nanotube assemblies on graphite
           superstructures as free-standing lithium-ion battery anodes
    • Abstract: Publication date: Available online 13 October 2018Source: CarbonAuthor(s): Yiran Yan, Changling Li, Chueh Liu, Zafer Mutlu, Bo Dong, Jingjing Liu, Cengiz S. Ozkan, Mihrimah Ozkan Carbonaceous materials are intensively used as additives or active electrode materials in lithium-ion battery (LIB) industry due to their stable chemical and physical properties. Compared to developing next-generation high-capacity non-carbonaceous anode materials, improvement on current carbonaceous materials could lead to instant commercial values due to less process modifications to the battery manufacturing. Here, we report a facile approach to synthesize carbon nanotubes (CNTs) with controlled assemblies: well-dispersed CNTs vs. bundled CNTs. Furthermore, we incorporated these carbon nanotubes onto three-dimensional (3D) graphite foams as free-standing anodes for lithium-ion batteries. This hierarchical 3D network provided high surface area and ultra-high conductivity with enhanced battery capacity. With controlled growth conditions, the assembly of CNTs can be changed from bundled state to dispersed state, resulting in a significant improvement in electrochemical performance. The dispersed CNTs showed a higher specific capacity of above 800 mAhg−1 over 120 cycles, while CNT bundles exhibited a specific capacity of 500 mAhg−1. The loose structure of well-dispersed CNTs provides sufficient active interfaces between electrolyte and materials, as well as shortened ion transport path. Insights can be gained in improving state-of-the-art battery performance by controlling the bulk assemblies of CNT additives.Graphical abstractImage 1
       
  • The interplay between multiple toughening mechanisms in nanocomposites
           with spatially distributed and oriented carbon nanotubes as revealed by
           dual-scale simulations
    • Abstract: Publication date: Available online 12 October 2018Source: CarbonAuthor(s): Qiang Liu, Stepan V. Lomov, Larissa Gorbatikh The success of carbon nanotubes (CNTs) in increasing toughness of polymers and their composites is often attributed to the additional energy consumed by CNT debonding and pull out. In this work we demonstrate that this mechanism alone can only lead to modest improvements in toughness and that the true toughening power of CNTs lies in activation of multiple mechanisms. Our virtual experiments reveal three mechanisms: 1) suppression of stress concentrations leading to delay in damage initiation, 2) damage diffusion/crack branching and 3) CNT debonding and pull-out. The first two mechanisms dominate energy dissipation although they have received less attention in the literature. These mechanisms act concurrently at different scales and have complex dependence on the morphology of the CNT network and properties of the CNT/matrix interface. When CNTs’ position, orientation and compatibility with polymer are optimized, the strength and toughness of the nanocomposite can be increased significantly (in the studied case by 90% and 277%, respectively, compared to unfilled polymer). Without morphological optimization these improvements were only 6% and 14%, respectively. Thus, for strengthening and toughening of nanocomposite structures, it is insufficient to only modify the interface, one also needs to optimize CNTs’ spatial distribution and orientation.Graphical abstractImage
       
  • Tailored crystalline width and wall thickness of an annealed 3D carbon
           foam composites and its mechanical property
    • Abstract: Publication date: Available online 12 October 2018Source: CarbonAuthor(s): J. Marx, S. Roth, A. Brouschkin, D. Smazna, Y.K. Mishra, K. Schulte, R. Adelung, B. Fiedler Carbon nanostructures in form of 3D carbon foams are mainly popular in materials community because of their ultralow densities, variable morphologies, and remarkable properties, etc. One of these foams is Aerographite, which exhibits a tetrapodal interconnected morphology. Similar to other synthetic carbon structures, the lattice defects are formed during the synthesis of Aerographite, which can be healed by a post-thermal treatment. Aerographite shows a property dependency on wall thickness (number of graphitic layers), which affects both, the electrical and mechanical properties. In this study, the wall thickness is tailored by varying of the total reaction time during the replication process. The influence of the thermal treatment of Aerographite on its mechanical performance in an Aerographite-epoxy nanocomposite, by determining the fracture toughness (K1C) in three-point bending tests (SEN-3PB), is investigated. An increase of the fracture toughness with increasing wall thickness is observed for untreated Aerographite. The graphitization of Aerographite leads to a reduction of the mechanical properties, by increasing the crystalline width. Consequently, the measured fracture toughness is dependent on the graphitization, the calculated crystalline width and the wall thickness of tubes in the hollow Aerographite tetrapodal network. Finally, based on these relations, a phenomenological mechanical failure model is developed and briefly discussed.Graphical abstractImage 1
       
  • Trace electrosprayed nanopolystyrene facilitated dispersion of multiwalled
           carbon nanotubes: Simultaneously strengthening and toughening epoxy
    • Abstract: Publication date: Available online 12 October 2018Source: CarbonAuthor(s): Hongbo Gu, Hongyuan Zhang, Chao Ma, Xiaojiang Xu, Yaqing Wang, Zicheng Wang, Renbo Wei, Hu Liu, Chuntai Liu, Qian Shao, Xianmin Mai, Zhanhu Guo The search of multifunctional epoxy nanocomposites with both strength and toughness combined with smart features such as electrical conductivity is essential in design of advanced materials. In this work, by utilizing a binary nanofiller strategy, both strength and toughness as well as high electrical conductivity are obtained in epoxy with trace nanopolystyrene grafted with epichlorohydrin (nano g-PS) to facilitate the dispersion of multi-walled carbon nanotubes (MWCNTs). The increased tensile strength (37.6%) and flexural strength (34.4%) are acquired in nano g-PS (0.0677 vol%)/MWCNTs (0.0335 vol%)/epoxy in contrast to pure epoxy. A remarkably improved tensile toughness up to 379.2% and an increased elongation at break up to 208.3% are obtained in this epoxy nanohybrid. The synergistic interactions among nano g-PS, MWCNTs and epoxy matrix as well as the state transition of nano g-PS from glassy state to fluid state provide an improved dispersion of nanofillers which is responsible for the increased electrical conductivity and enhanced mechanical properties. The decreased surface resistivity allows these nanohybrids to sufficiently dissipate surface charges as an antistatic material. This work provides an effective way to disperse carbon nanotubes with small amount of thermoplastic PS to simultaneously strengthen and toughen the thermosetting epoxy while introducing highly conductive function.Graphical abstractImage 1
       
  • Joule heating-induced sp2-Restoration in graphene fibers
    • Abstract: Publication date: Available online 12 October 2018Source: CarbonAuthor(s): Sung Hyun Noh, Wonsik Eom, Won Jun Lee, Hun Park, Swapnil B. Ambade, Sang Ouk Kim, Tae Hee Han Joule heating can instantaneously achieve high temperatures (>2000 °C) by applying electrical current on a resistive material. This ohmic heating by the passage of an electric current through a conducting domain may effectively heal the defective sites (i.e., vacancies, structural defects, and sp3 oxygen groups) of graphene oxide (GO) and revert them into sp2 domains. Indeed, the direction of electric field controls the texture of GO with preferential alignment, which significantly affects the transport properties along the fiber axis. Here we present electrical current-induced manipulation of resistive domain (i.e. Joule heating) as an effective healing method for the defect sites in GO fibers (GOFs). Systematic control of input current restores the sp2 lattice structures within fibers in a well-controlled manner. Structural evolution mechanism is proposed for multilayer stacked graphitic structures as well as graphene sheet plane under the reduction process. This defect-healing principle is rapid, environmentally benign and energy efficient, compared to other defect restoration methods, and yields tailored-aligned fibers with a high current-carrying capability and facile charge transport, which is potentially beneficial for power cables and other relevant applications.Graphical abstractCurrent-induced self-annealing on graphene fibers for the healing of defects in graphene fibers.Image 1
       
  • In situ construction of nitrogen-doped graphene with surface-grown carbon
           nanotubes as a multifactorial synergistic catalyst for oxygen reduction
    • Abstract: Publication date: Available online 12 October 2018Source: CarbonAuthor(s): Ailing Song, Lei Cao, Wang Yang, Wu Yang, Lixin Wang, Zhipeng Ma, Guangjie Shao Two-dimensional graphene-based materials attract much attention in catalysis due to their high specific surface area and continuous electron transport pathways. However, this material is suffering layer stacking, resulting the masked of most surface active sites, and also being detrimental to mass transfer. Based on the amine-aldehyde resin polymerization method, we constructed a multifactorial synergistic catalyst of nitrogen-doped graphene with surface in situ grown carbon nanotubes (CNTs, Co@NGC). This construction involving two to three-dimensional structural transformation not only avoids layer stacking, but further facilitates the formation of more well-dispersed Co and N species embedded into carbon networks of graphene and CNTs (to form Co-N and C-N active sites) and increases the accessibility of active sites. After evaluating the test results of comparative experiments, we elucidated the formation process and the activity source of the catalyst. The prepared optimal Co@NGC-800 realized praiseworthy oxygen reduction activity in alkaline media, showing an onset potential of 1.00 V (vs RHE) and a half-wave potential of 0.86 V (vs RHE). Enhanced stability attained comparing with NG (nitrogen doped graphene without the growth of CNTs), the half-wave potential of Co@NGC-800 lost only 8 mV after 40 000 s chronoamperometry.Graphical abstractImage 1
       
  • Odd-even phonon transport effects in strained carbon atomic chains
           bridging graphene nanoribbon electrodes
    • Abstract: Publication date: Available online 12 October 2018Source: CarbonAuthor(s): Hu Sung Kim, Tae Hyung Kim, Yong-Hoon Kim Based on first-principles approaches, we study the ballistic phonon transport characteristics of finite monatomic carbon chains stretched between graphene nanoribbons, an sp1-sp2 hybrid carbon nanostructure that has recently seen significant experimental advances in its synthesis. We find that the lattice thermal conductance anomalously increases with tensile strain for the even-numbered carbon chains that adopt the alternating bond-length polyyne configuration. On the other hand, in the odd-numbered carbon chain cases, which assume the equal bond-length cumulene configuration, phonon conductance decreases with increasing strain. We show that the strong odd-even phonon transport effects originate from the characteristic longitudinal acoustic phonon modes of carbon wires and their unique strain-induced redshifts with respect to graphene nanoribbon phonon modes. The novel phonon transport properties and their atomistic mechanisms revealed in this work will provide valuable guidelines in designing hybrid carbon nanostructures for next-generation device applications such as nano-biosensors.Graphical abstractImage 1
       
  • The Taxonomy of Graphite Nanoplatelets and the Influence of Nanocomposite
           Processing
    • Abstract: Publication date: Available online 12 October 2018Source: CarbonAuthor(s): Zheling Li, Thomas J.A. Slater, Xinyu Ma, Yingjie Yu, Robert J. Young, Timothy L. Burnett The reinforcement efficiency of graphene in a nanocomposite relies on the size, morphology, defects and agglomeration of flakes. However, the characterisation is usually undertaken only for the raw materials and any changes that take place during processing are not taken into consideration. In this work, epoxy nanocomposites reinforced by graphite nanoplatelet (GNP) were prepared and nano-scale X-ray computed tomography was used to visualize the geometry, morphology and defects of the flakes, as well as the three dimensional agglomerates that are normally difficult to characterise by other techniques. In combination with micromechanical analysis, the taxonomy of the nanoplatelets is shown to be of great importance in controlling the mechanical properties of nanocomposites, and this has been shown to explain the deviations of the predictions of micromechanical models from the measured values. Particularly, it is shown that taking single average values of flake size may not be appropriate and the entire distribution of flake size need to be taken into consideration. Furthermore, it is shown that the Young’s modulus of a nanocomposite is controlled principally by a small number of large flakes and that volume average distributions of flake size are more appropriate to use rather than number average ones.Graphical abstractImage
       
  • Molten salt synthesis of hierarchical porous N-doped carbon
           submicrospheres for multifunctional applications: High performance
           supercapacitor, dye removal and CO2 capture
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Junyi Li, Liang Tian, Feng Liang, Junkai Wang, Lei Han, Jun Zhang, Shengtao Ge, Longhao Dong, Haijun Zhang, Shaowei Zhang Hierarchical porous N-doped carbon submicrospheres (HPNCs) are synthesized at 1000 °C by a facile molten salt method using diaminomaleonitrile as a precursor, iron trichloride as a catalyst, and ZnCl2-KCl to form the molten salt medium. The results indicated that the pore structure of resultant HPNCs could be tuned by changing the amount of iron catalyst, and those prepared with adding 7.1 wt% FeCl3·6H2O showed the highest specific surface area (3155 m2/g) and largest hierarchical pore volume (2.2 cm3/g) with micropore and mesopore surface areas of 808 m2/g and 2347 m2/g, respectively, in addition to their high mesopore ratio up to 84.4%. The resultant HPNCs showed outstanding specific capacitance up to 455 F/g in 6 M KOH electrolyte solution at a current density of 0.5 A/g, a considerably high energy density of 93.6 Wh/kg and high capacitance retention of 95% after 5000 cycles. Moreover, they exhibited high adsorption capacities of 812.2 mg/g and 805.2 mg/g, for methylene blue and methyl orange adsorption, respectively, and high CO2 adsorption capacity of 3.4 mmol/g at 25 °C and at an equilibrium pressure of 1 bar.Graphical abstractHierarchical porous N-doped carbon submicrospheres (HPNCs) are synthesized by a facile molten salt method. The as-prepared HPNCs not only exhibit high supercapacitance performance, but also possess ultrahigh adsorption performances for chemical dyes and CO2.Image 1
       
  • In-situ carboxylation of graphene by chemical vapor deposition growth for
           biosensing
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Sandra Cortijo-Campos, Leo Álvarez-Fraga, Gil Gonçalves, Mercedes Vila, Patricia Álvarez, Rosa Menéndez, Alicia de Andrés, Carlos Prieto A new approach for in-situ specific functionalization of graphene with carboxylic groups through a single-step growth is presented. Depending on the fabrication parameters, it is possible to synthesize functionalized single layer or multilayer graphene. The homogeneity and functionalization degree are evaluated combining micro-Raman and XPS spectroscopies. The obtained COOH content reaches around 5%, similar to the values obtained by the other methods but with significantly lower contents of the other oxygen groups (carbonyl and hydroxyl) and of other sp3 defects which are detrimental for electronic transport. The obtained COOH- functionalized single-layer graphene presents optimum values of the sheet resistance, around 8 kΩ, and high mobility, around 800 cm2V−1s−1. Anchoring of antibodies is demonstrated through the immobilization of IgG1–FITC by the carbodiimide method, showing that these COOH- functionalized single-layer graphene can be very promising materials for electronic sensing applications.Graphical abstractImage 1
       
  • New nanoporous graphyne monolayer as nodal line semimetal: Double Dirac
           points with an ultrahigh Fermi velocity
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Linyang Li, Xiangru Kong, François M. Peeters Two-dimensional (2D) carbon materials play an important role in nanomaterials. We propose a new carbon monolayer, named hexagonal-4,4,4-graphyne (H4,4,4-graphyne), which is a nanoporous structure composed of rectangular carbon rings and triple bonds of carbon. Using first-principles calculations, we systematically studied the structure, stability, and band structure of this new material. We found that its total energy is lower than that of experimentally synthesized β-graphdiyne and it is stable at least up to 1500 K. In contrast to the single Dirac point band structure of other 2D carbon monolayers, the band structure of H4,4,4-graphyne exhibits double Dirac points along the high-symmetry points and the corresponding Fermi velocities (1.04–1.27 × 106 m/s) are asymmetric and higher than that of graphene. The origin of these double Dirac points is traced back to the nodal line states, which can be well explained by a tight-binding model. The H4,4,4-graphyne forms a moiré superstructure when placed on top of a hexagonal boron nitride substrate. These properties make H4,4,4-graphyne a promising semimetal material for applications in high-speed electronic devices.Graphical abstractImage 1
       
  • Cobalt and nitrogen codoped ultrathin porous carbon nanosheets as
           bifunctional electrocatalysts for oxygen reduction and evolution
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Youchen Tang, Ruliang Liu, Shaohong Liu, Bingna Zheng, Yuheng Lu, Ruowen Fu, Dingcai Wu, Mingqiu Zhang, Minzhi Rong Development of efficient, low-cost, and durable electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is scientifically and technologically important for the conversion and storage of renewable energy. Herein, cobalt and nitrogen codoped ultrathin porous carbon nanosheet (Co-N-PCN) is developed by directly carbonizing the graphene oxide sandwiched cobalt ion adsorbed polyaniline-co-polypyrrole (PACP) precursors. The nitrogen-rich PACP favors the formation of abundant Co-Nx-C active species, while the 2D ultrathin nanosheet structure ensures the high exposure of the generated Co-Nx-C active sites to the electrolyte. In addition, the sandwiched graphene acts as the conductive backbone to facilitate fast charge transfer and enhance the electrode conductivity. Benefiting from the synergistic effect, the Co-N-PCN presents superior electrocatalytic properties with low overpotentials and favorable kinetics to Pt and RuO2 as a bifunctional electrocatalyst for ORR and OER. Remarkably, the potential difference of OER and ORR (ΔE = Ej=10 - E1/2) is as low as 0.81 V in 0.1 M KOH, indicating the Co-N-PCN outperforms most of the previously reported bifunctional electrocatalysts.Graphical abstractImage 1
       
  • Green synthesis of transition metal nanocrystals encapsulated into
           nitrogen-doped carbon nanotubes for efficient carbon dioxide capture
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Sreetama Ghosh, Sundara Ramaprabhu The present study aims to explore the ability of transition metal encapsulated nitrogen-doped carbon nanotubes (M@NCNTs) as efficient CO2 adsorbent over a wide range of temperature and pressure. Initially, a single-step, economical, easily scalable and environment-friendly thermal decomposition technique was undertaken to synthesize the M@NCNTs. Their structure, surface morphology and composition were comprehensively studied using different characterization techniques. The mechanism of metal (M = Fe/Co/Ni) encapsulation inside the bamboo-shaped NCNTs was thoroughly investigated via X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) analysis at different stages of pyrolysis. High pressure (≤20 bar) and low pressure (≤1 bar) CO2 uptake capacities reveal that M@NCNTs show much higher adsorption capacities in comparison to pristine multiwalled carbon nanotubes (MWNTs) and pure nitrogen doped carbon nanotubes (NCNTs). The uptake capacity was seen to follow a trend of Fe/Fe3C@NCNTs > Co@NCNTs > Ni@NCNTs in both high as well as low pressure adsorption studies and in this aspect the interaction of CO2 with transition metals has been discussed. The encapsulated metal nanoparticles along with high surface area NCNTs, therefore, play a synergistic role in enhancement of gas uptake properties. To the best of our knowledge, this is the first report on metal encapsulated NCNTs being investigated for CO2 capture.Graphical abstractImage 1
       
  • Effect of fiber lay-up configuration on the electromagnetic interference
           shielding effectiveness of continuous carbon fiber polymer-matrix
           composite
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): D.D.L. Chung, Asma A. Eddib Continuous carbon fiber polymer-matrix multifunctional structural composites capable of electromagnetic interference (EMI) shielding are needed for electronics and radiation sources. The laminate's fiber lay-up configuration affects the shielding effectiveness, as shown in this work for unmodified conventional carbon fiber polymer-matrix composite laminates with high-strength PAN-based carbon fiber and a polyamide thermoplastic matrix. The radiation is normal-incidence unpolarized plane wave, as commonly used. The shielding is dominated by absorption rather than reflection – more so for crossply composites than unidirectional composites. Due to the electrical conductivity longitudinal-to-transverse ratio of 930 for a lamina, the absorption-loss/thickness longitudinal-to-transverse ratio is 30 at 1.0 GHz. This factor of 30 means that the contribution of the fibers transverse to the electric field to absorption is negligible compared to that of the fibers parallel to the electric field. The ratio of absorption-loss/thickness for the crossply composite to that for the unidirectional composite with the same number of laminae is ∼4, and the ratio of the reflection loss for the crossply composite to that for the unidirectional composite is ∼2. The values of these ratios are consistent with electromagnetic theory for unpolarized radiation. This work strengthens the science base for the design of continuous fiber composites for shielding.Graphical abstractImage 1
       
  • Realizing robust half-metallic transport with chemically modified graphene
           nanoribbons
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Lingling Song, Shaopeng Jin, Peng Jiang, Hua Hao, Xiaohong Zheng, Lei Zhang Although many chemical modification schemes for achieving half-metallicity in zigzag-edged graphene nanoribbons (ZGNRs) have been proposed, practically, half-metallic transport is hardly observable with them due to the resulting negligible energy difference of the anti-ferromagnetic (AF) and ferromagnetic (F) configurations between the two edges. We propose a scheme to achieve robust half-metallic transport by such ZGNRs in which central carbon atoms are substituted by BN pairs. We build transport junctions by connecting the top edge of one ribbon with the bottom edge of another through a carbon tetragon or a carbon hexagon. For both connection styles, we consider two different relative orientations of the BN pairs in the two ribbons, namely, a “BN-BN” case with the BN pairs in the same direction and a “BN-NB” case with the BN pairs in the opposite directions. It is found that, for both connection styles, we can always get a BN configuration where the junction is always in a perfect half-metallic state, independent of the magnetic configurations. It is understood by the matching or mismatching of the spin polarity and spatial separation of the edge states of the two ribbons. This should be taken into consideration in the design of spintronic devices with graphene nanoribbons.Graphical abstractImage 1
       
  • Development of mesopores in superfine grain graphite neutron-irradiated at
           high fluence
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Cristian I. Contescu, José D. Arregui-Mena, Anne A. Campbell, Philip D. Edmondson, Nidia C. Gallego, Kentaro Takizawa, Yutai Katoh Microstructural changes induced by neutron irradiation of superfine grain graphite G347A (Tokai Carbon, Japan) were examined by nitrogen adsorption at 77 K and by three microscopy techniques (SEM, TEM and FIB-SEM tomography). The specimens were irradiated at doses of up to 30 dpa, covering stages before and after the turnaround fluence at three temperatures (300, 450, 750 °C) of their irradiation envelope. The initial graphite densification at low fluences did not produce any detectable effect in the pore size range (
       
  • Raman and IR signature of pristine and BN- doped γ-graphyne from
           first-principle
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Barnali Bhattacharya, Nicola Seriani, Utpal Sarkar The present paper aims to provide in-depth analysis of Raman and IR spectra as well as the assigned vibrational modes of pristine and BN substituted graphynes, considering different dopant sites and concentrations. We have explored the implication of vibrational modes related with the Raman and IR line of pristine graphyne and BN-doped graphynes. The Raman and IR spectra of BN substituted graphyne show quite distinct feature than pristine graphyne and monolayer h-BN sheet. It also shows regular dependence on doping site as well as doping concentrations. Raman spectra help to detect the substitution site of BN while IR spectra help to identify the BN concentration. Hence the combination of IR and Raman spectra would be useful in detecting BN-doped graphyne during synthesis. Thus this study would help the experimentalist in sample characterization in near future.Graphical abstractImage 1
       
  • MOF derived N-doped carbon coated CoP particle/carbon nanotube composite
           for efficient oxygen evolution reaction
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Xian Wang, Zuju Ma, Lulu Chai, Leqiong Xu, Ziyi Zhu, Yue Hu, Jinjie Qian, Shaoming Huang Growing demand for clean and renewable energy resources has sparked intensive research on the development of an effective strategy to prepare non-noble metal electrocatalysts for oxygen evolution reaction (OER). Herein, we report a new type of N-doped carbon coated CoP particle/carbon nanotube composite (CNT-NC-CoP) has been synthesized by in situ nucleation and growth of ZIF-67 nanoparticles onto carbon nanotubes, which subsequently is treated with carbonization and phosphorization. Unique hierarchical structure endows as-obtained CNT-NC-CoP with high specific surface area, abundant exposed active sites, quick ion diffusion path, and good electrical conductivity, thus exhibiting the highest electrocatalytic capability with the low overpotential of 251 mV at the current density of 10 mA cm−2 and remaining long-term durability (overlapping LSV curve after 10 h). Besides, density functional theory (DFT) calculations reveal that CoOOH/graphene charged surfaces are more effective for facilitating intermediates adsorption and improving the corresponding catalytic activity.Graphical abstractSchematic illustration of the synthesis of N-doped carbon coated CoP particle/carbon nanotube composite, which has been prepared by in situ growth of ZIF-67 nanoparticles onto PDA-coated carbon nanotubes, subsequently being treated with carbonization and phosphorization.Image 1
       
  • Internal structure of soot particles in a diffusion flame
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Maria L. Botero, Yuan Sheng, Jethro Akroyd, Jacob Martin, Jochen A.H. Dreyer, Wenming Yang, Markus Kraft The evolution of the internal structure of soot particles was studied in a coflow diffusion flame. Soot particles from the flame were imaged using high resolution transmission electron microscopy. An algorithm to quantify the nano-structure of the particles was extended to study the radial distribution of fringes within the particles. The approximate size of the molecules in the particles was calculated from the fringe lengths, assuming planar peri-condensed PAHs. The molecules are slightly larger (∼16 rings) and more stacked at the core than at the surface (∼12 rings) of the youngest particles sampled, suggesting that the particles could be formed via the stabilisation of a nuclei of larger PAHs and condensation of smaller PAHs on their surface. In the lower-temperature region of the flame the molecules grow mainly at the surface of the particles, whereas the molecules in the core of the particles become less stacked and slightly smaller, indicating some degree of nano-structural mobility. In the higher-temperature region of the flame, a graphitisation process takes place, with the development of a shell of longer (∼20 rings), flatter and more compact molecules, and an immobilised amorphous core. At the tip of the flame the particles are oxidised, mainly through surface oxidation.Graphical abstractImage 1
       
  • In silico synthesis of carbon molecular sieves for high-performance air
           separation
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Yasuyuki Yamane, Hideki Tanaka, Minoru T. Miyahara We performed nonequilibrium molecular dynamics simulations of the chemical vapor deposition (CVD) of hydrocarbons on a precursor-activated carbon model with a slit-like pore (in silico CVD simulation) to explore design guidelines for the synthesis of high-performance carbon molecular sieves (CMSs) for air-separation purposes. The dependence of the CVD process on gas species was investigated using “united-atom” hydrocarbons mimicking ethylene, benzene, toluene, and mesitylene. The obtained CMS models were then used to evaluation the diffusion rate constants of O2 and N2 using the transition state theory. We also constructed idealized carbon pore structures that extracted the characteristics of the CMS models obtained via the in silico CVD simulations to understand the relation between the size and geometry of pore mouths, diffusion rate constants, and kinetic O2 selectivity. We found that most of the simulated results were supported by experimental evidence. Furthermore, we conclude that a high-performance CMS for air separation requires the development of thin amorphous carbon at the pore mouths of the precursor-activated carbon by CVD, which provides a single energy barrier for O2 diffusion and effectively prevents the formation of multiple energy barriers.Graphical abstractImage 1
       
  • Incorporation and recovery of SWNTs through phase behavior and aggregates
           transition induced by changes in pH in a catanionic surfactants system
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Zhaolan Zhai, Xinyan Yan, Ji Xu, Zhanqian Song, Shibin Shang, Xiaoping Rao The phase behavior and aggregates induced by changes in pH in a sodium N-tetradecyl-maleimidepimaric carboxylate (C14-MPA-Na)/cetyltrimethylammonium bromide (CTAB) system have been investigated using rheology and cryogenic transmission electron microscopy (cryo-TEM). Viscoelastic solutions at a pH between 6.40 and 1.41, opalescent blue solutions at a pH between 1.41 and 1.32 and aqueous surfactant two-phase systems (ASTPs) at a pH between 1.32 and 0.56 are formed sequentially. The microstructures in the viscoelastic solutions are wormlike micelles that partially transform to vesicles in the opalescent blue solutions. The aggregates in the upper phase of the ASTPs are vesicles and lamellar micelles, and in the lower phase are spherical micelles. Further, Single-walled carbon nanotubes (SWNTs) were successfully hybridized into the wormlike micellar viscoelastic solutions. cryo-TEM, UV–Vis-IR, near-infrared photoluminescence (NIR-PL) and UV–Vis spectroscopy were used to study the dispersion of SWNTs in the viscoelastic solutions, and the results showed SWNTs can remain dispersed for more than 6 months at pH 6.40. The results obtained from rheology showed that the hybridization of SWNTs will not affect the aggregates and viscoelasticity compared that to the native viscoelastic solution. Above more, the SWNTs could be recycled by the pH-switched phase behaviors between viscoelastic solutions and ASTPs.Graphical abstractSWNTs are successfully hybridized and recycled using wormlike micellar viscoelastic solutions which could transform into ATSPs by changing pH.Image 1
       
  • Multifunctional broadband microwave absorption of flexible graphene
           composites
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Kai-Lun Zhang, Jun-Ying Zhang, Zhi-Ling Hou, Song Bi, Quan-Liang Zhao Stable broadband microwave absorption is widely interested for their irreplaceable role in stealth technology for multiband microwave communication and detection. In this paper, a flexible broadband microwave absorber with self-recoverability was fabricated by self-assembling graphene sheets into polypropylene 3D framework. The as-fabricated absorber has a full-band absorption (more than 90%) in the working ranges of microwave communication and detection in military radars (2–40 GHz and 75–110 GHz), exhibiting larger bandwidth than the absorbers reported in literature. Furthermore, its bandwidth with more than 97% absorption (Reflection loss ≤ −15 dB) is as large as 62.73 GHz. The impressive absorption ability attributes to the impedance matching to free-space, coupling of multiple resonances and edge scattering of the microwave absorber, which could be manipulated by the pattern design of SA. For both the transverse electric and transverse magnetic polarizations, the broadband absorptions keep stable in a wide range of incidence angle, and they are recoverable after press and folding. The stable broadband absorption and recoverability make the flexible absorber suitable for the stealth of deformable objects like robots or foldable wings.Graphical abstractImage 1The multifunctional absorber, fabricated by flexible graphene composites, exhibits stable broadband absorption performance and excellent self-recovery, promising effective stealth of deformable objects like robots or foldable wings.
       
  • From high pressure radial collapse to graphene ribbon formation in
           triple-wall carbon nanotubes
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): S.D. Silva-Santos, R.S. Alencar, A.L. Aguiar, Y.A. Kim, H. Muramatsu, M. Endo, N.P. Blanchard, A. San-Miguel, A.G. Souza Filho The radial stability and the irreversible transformation of triple-wall carbon nanotubes (TWCNTs) bundles are investigated at high pressure conditions both experimentally and theoretically (exp. up 72 GPa). The tubes having a mean internal diameter of 0.83nm and graphite-like intertube distance, show an onset of the radial collapse evidenced by the evolution of optical phonons. The nanotube collapse onset is observed at ∼22 GPa completes for the two external tubes at ∼29 GPa, however the innermost tube remains stable up to ∼37 GPa. Molecular dynamic calculations performed on smaller diameter TWCNTs bundles, as a model system, confirmed the multiple-stage pressure-induced collapse process. An analytical expression for the collapse pressure of carbon nanotubes having an arbitrary number of walls is proposed. Our experiments and modelling show that for pressures beyond ∼ 60 GPa an irreversible structural transformation of TWCNTs takes place. Ex situ transmission electron microscopy characterization on the recovered sample from 72 GPa revealed the mechanical failure of carbon nanotubes which evolve towards ribbon-like structures as corroborated by Raman spectroscopy. Modelling the tubes evolution at high pressure and high temperature showed the formation of new structures ranging from ribbon-like to graphite-like with either different degrees of amorphization or sp3 interlinking.Graphical abstractImage 1
       
  • Oxygen-enriched carbon nanotubes as a bifunctional catalyst promote the
           oxygen reduction/evolution reactions in Li-O2 batteries
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Lei Qin, Wei Lv, Wei Wei, Feiyu Kang, Dengyun Zhai, Quan-Hong Yang The aprotic lithium-oxygen (Li-O2) batteries based on carbon-based oxygen cathodes usually suffer from low round-trip efficiency. Here we adopt oxygen-enriched carbon nanotubes (CNTs) by acid etching treatment as the cathode, in which a low voltage plateau at ∼3.5 V during charge is exhibited and the initial round-trip efficiency is increased from 69.9% to 76.0%. An optimized integration of electrocatalytic property and electrical conductivity is crucial for the oxidized CNTs cathode to enhance the capacity and cycling performance. In particular, the surface oxygen groups can facilitate the electrocatalysis of O2 with the enhanced oxygen reduction reaction activity and induce defective lithium peroxide (Li2O2) formation due to their preferential adsorption of O2 on the oxidized CNTs. Compared to the high crystalline Li2O2 toroids, the defective Li2O2 with poor crystallinity could be decomposed at a lower charge potential, contributing to the enhanced round-trip efficiency of Li-O2 batteries.Graphical abstractImage 1
       
  • A new approach in functionalization of carbon nanoparticles for
           optoelectronically relevant carbon dots and beyond
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Xianyan Ren, Weixiong Liang, Ping Wang, Christopher E. Bunker, Montrez Coleman, Lindsay Rose Teisl, Li Cao, Ya-Ping Sun Carbon dots (CDots), generally small carbon nanoparticles with surface passivation by a soft corona-like layer of mostly organic species, have been actively pursued for potential applications in optoelectronics, including various functions that have been served by some popular fullerene derivatives. For the preparation of CDots, chemical functionalization of pre-processed and selected small carbon nanoparticles by organic molecules, so far mostly molecules with primary and secondary amine groups, has been an effective method. In this study, carbon nanoparticles were functionalized by N-ethylcarbazole (NEC) under microwave-assisted reaction conditions for NEC-CDots, analogous but with advantages to the CDots of surface functionalization by poly(N-vinylcarbazole) (PVK, which holds a special place in optoelectronics). NEC molecules can apparently be activated under the reaction conditions for reactive functionalities such as radicals to bind to surface carbons of the nanoparticles, consistent with the observed high stability of NEC-CDots. These dots, likely with a unique surface passivation scheme, exhibited optical properties and photoinduced redox characteristics similar to those found in other high-performance CDots. The potentially broad applicability of the new functionalization approach is discussed, so are implications of the unique surface passivation of carbon nanoparticles by the carbazole moieties.Graphical abstractImage
       
  • Coal tar- and residual oil-derived porous carbon as metal-free catalyst
           for nitroarene reduction to aminoarene
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Qinhong Wei, Fangfang Qin, Qingxiang Ma, Wenzhong Shen Nitroarenes reduction is an important technology in the industrial production of aminoarenes. In this work, we presented an environment-friendly and low-cost green synthesis route for preparation of oxygen and nitrogen co-doped porous carbon (ONPC) via acid oxidation and alkali activation methods using coal tar- and residual oil-based as starting materials, and the prepared ONPC was employed as metal-free carbon catalyst for nitroarenes reduction to aminoarenes in the presence of hydrazine hydrate. This ONPC catalyst showed much higher catalytic activity as compared to those of un-doped porous carbon (PC), activated carbon (AC) and carbon black, which was attributed to its large surface area and developed pore structure as well as O and N co-doping. Additionally, it also exhibited a versatility in various aromatic nitro-compounds reduction to relative aromatic amines. Experimental results by using model catalysts to simulate different carbons with various oxygen-containing groups proved that carbonyl groups were more favorable for nitrobenzene reduction to aniline. Upon co-doping O and N into PC, the two kinds of introduced species synergistically promoted the catalytic activity of PC. Good performance together with low-cost preparation makes oxygen and nitrogen co-doped porous carbon a potential substitution of supported metal catalyst for nitroarenes reduction.Graphical abstractImage 1
       
  • Electromagnetic interference shielding MWCNT-Fe3O4@Ag/epoxy nanocomposites
           with satisfactory thermal conductivity and high thermal stability
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Lei Wang, Hua Qiu, Chaobo Liang, Ping Song, Yixin Han, Yixuan Han, Junwei Gu, Jie Kong, Duo Pan, Zhanhu Guo Hierarchical composite nanoparticles of multiwall carbon nanotube (MWCNT)-Fe3O4@Ag combining electrical conductivity and magnetism were obtained from acyl-amine reaction between carboxylation of Fe3O4@Ag (Fe3O4@Ag-COOH) nanoparticles and amino functionalized MWCNTs (MWCNTs-NH2). Finally, the MWCNT-Fe3O4@Ag/epoxy nanocomposites were fabricated via blending-casting method. When the mass ratio of MWCNTs-NH2 to Fe3O4@Ag-COOH was 9:1 (MF-10), the corresponding epoxy nanocomposites presented an optimal electrical conductivity and electromagnetic interference (EMI) shielding effectiveness (SE). Furthermore, the MF-10/epoxy nanocomposites with 15 wt% MF-10 presented a satisfying EMI SE of 35 dB and high electrical conductivity of 0.280 S/cm, satisfactory thermal conductivity (thermally conductive coefficient, λ of 0.46 W/mK), outstanding Young's modulus of 4.60 GPa & hardness value of 0.26 GPa and excellent thermal stability (THRI of 183.4 °C). The introduction of Fe3O4@Ag nanoparticles not only enhanced the interaction among MF-10, so as to promote the formation of conductive networks, leading to higher λ and EMI SE value, but also contributed to hysteresis loss of electromagnetic waves, and offered more interfaces to reflect and reabsorb electromagnetic waves, resulting in highly improved attenuation of electromagnetic waves.Graphical abstractImage
       
  • CNT fibres as dual counter-electrode/current-collector in highly efficient
           and stable dye-sensitized solar cells
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Alfonso Monreal-Bernal, Juan J. Vilatela, Rubén D. Costa This work demonstrates that carbon nanotube (CNT) fiber electrodes consisting of a mesoporous and crystalline network of few-layer CNTs can be used as free-standing, unipolar, and dual counter-electrode (CE)/current-collectors in highly efficient and stable planar dye-sensitized solar cells (DSSCs). After device optimization, particularly in terms of photoanode thickness, the solar energy conversion efficiency reached 8.8%, which is comparable to devices with platinum CE (8.7%). Through study of symmetric cells using electrochemical impedance spectroscopy (EIS) measurements, this work discloses the first clear identification of the different processes involved in the use of CNTf electrodes as CE, namely bulk ion diffusion, ion diffusion inside the mesoporous electrode, and charge transfer at the CNT surface. These results provide clear directors for a further understanding of the fundamental catalytic properties of CNTf fibers towards improving their photoelectrochemical features. Finally, we assemble new device architectures, namely i) a free-standing CNT-CEs (unipolar electrode) device with two photoanodes facing each other to circumvent the lack of transparency of CNTs without losing performance, and ii) large-area solar cells (>10 cm2) with 10 devices interconnected in parallel along 1 m continuous CNTf-CE, featuring efficiencies comparable to the-state-of-the-art carbon-based DSSC modules.Graphical abstractImage 1
       
  • Investigation of multiband plasmonic metamaterial perfect absorbers based
           on graphene ribbons by the phase-coupled method
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Hongju Li, Chuansheng Ji, Yongze Ren, Jigang Hu, Meng Qin, Lingling Wang We develop an original phase-coupled method to realize multispectral metamaterial near-unity absorbers based on spatially separated graphene ribbon arrays with mid-infrared plasmonic resonances. The results both from the coupled-mode theory and finite-difference time-domain simulations reveal that in addition to the single-band absorption enabled by the bi-layer identical ribbon arrays, the outstanding dual-band perfect absorption is observed with the change in the phase between bi-layer ribbons only by varying the spacer thickness. The spectral positions of absorption peaks are tuned handily by small changes in ribbon widths and chemical potentials of graphene. Moreover, the triple-band absorber is achieved handily by the same principle and such absorbers are robust for nor-normal incident angles. The transfer matrix method is also utilized to uncover further the underlying physics of the phased-coupled-induced multispectral absorbers. Theoretical analysis are in excellent agreement with numerical calculations. The phase-coupled method thus provides new opportunities for obtaining multi-channel metamaterial perfect absorbers.Graphical abstractImage
       
  • X-ray absorption fine structure of carboxyl and other adventitious
           moieties attached to copper-supported graphene
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Hud Wahab, Hans-Christoph Mertins, Heiko Timmers, Terry J. Frankcombe The electronic and topographical structure of vapour-deposited graphene on copper is known to deteriorate in ambient conditions with time. This appears in X-ray absorption spectra at the carbon 1s edge as a reduction of π*- and σ*-resonance intensities and as fine structures at energies between the resonances. Our Density Functional Theory calculations show that the intensity reduction is due to the wrinkling of the graphene sheet, which may also cause a hitherto unobserved splitting of the σ*-resonance. The structure between the resonances can be due to adventitious adsorbates either at grain boundaries or at the graphene surface. The location of adsorbates, such as carboxyl, can be distinguished through the degree of anisotropy of the absorption. The hydrogen and carboxyl adsorbates at the graphene surface correspond to effectively isotropic peaks in the absorption spectrum, since the receiving carbon atom in the graphene sheet adopts sp3 hybridisation. In contrast, carboxyl groups at the edges of graphene grains are predicted to only cause the anisotropic absorption of photons. This informs the interpretation of an experimentally observed X-ray absorption peak at 288.3 eV, which often persists even after high-temperature vacuum-annealing of graphene and may be caused by adsorbates clustering at the basal plane.Graphical abstractImage 1
       
  • Enhancing conjugation degree and interfacial interactions to enhance
           dielectric properties of noncovalent functionalized graphene/poly
           (vinylidene fluoride) composites
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Weiyan Li, Zhongqian Song, Jing Qian, Zhongyang Tan, Huiying Chu, Xianyou Wu, Wei Nie, Xianghai Ran Introducing conductive nanofillers into a dielectric polymer is the most common way to tailor percolative composites with high dielectric constant. However, it usually contributes to large increase of dielectric loss, thereby restricting the improvement of practical energy storage capability. In this study, by regulating the conjugation degree of graphene derivatives and their interfacial interactions with polymer matrix, high dielectric constants were achieved for graphene/polymer composites and the loss was suppressed at a relatively low level. Electrochemical exfoliated graphene with high conjugation degree modified with a carboxyl-riched perylene derivative via π-π stacking interaction was used as a conductive nanofiller. Due to the high conjugation degree of graphene and carboxyl groups-induced high interfacial interactions with PVDF matrix, a high dielectric constant (ε = 480) was obtained at a low filler content of 0.74 vol% and the dielectric loss was suppressed as low as 0.27. The enhanced dielectric properties could be reasonably explained by a proposed model. This research provides a new and promising route for researchers to construct graphene/polymer composites with good dielectric properties for applications in modern electronics and electric power systems.Graphical abstractImage 1
       
  • Graphitic carbon nitrides (g-C3N4) with comparative discussion to carbon
           materials
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Michio Inagaki, Tomoki Tsumura, Tarou Kinumoto, Masahiro Toyoda Graphitic carbon nitride g-C3N4 was reviewed on its structure, synthesis, texture control, modification and applications, associating with the comparative discussion to carbon materials. Its basic structural unit is a layer of either triazine or heptazine cores consisting of C and N atoms, similar with a layer of hexagonal carbon rings of most of carbon materials. Fundamental synthesis process of g-C3N4 is pyrolysis of its precursors associated with different techniques, such as chemical vapor deposition, pressurizing, templating, doping, etc., as those applied for the synthesis of carbon materials. However, the properties of g-C3N4 are quite different from those of carbon materials; the former is hydrophilic but the latter is hydrophobic, and the former is photoactive for visible light but the latter is non-active. Here, g-C3N4 is reviewed on its structure, synthesis, texture control and modification, and application with comparative discussion to carbon materials.Graphical abstractImage
       
  • P(=O)(O)n+(n≤2)-linked+nano-Si/N-doped+C/ graphene+porous+foam+as+anodes+for+high-performance+lithium+ion+batteries&rft.title=Carbon&rft.issn=0008-6223&rft.date=&rft.volume=">Hierarchical CP(=O)(O)n (n≤2)-linked nano-Si/N-doped C/ graphene porous
           foam as anodes for high-performance lithium ion batteries
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Dan He, Xiao Huang, Mingqi Li Cooperative supermolecular self-assembly technique is introduced to synthesize a novel CP(=O)(O)n (n ≤ 2)-linked nano-Si/N-doped C/graphene anode composite for lithium ion batteries. This composite shows three-dimensional (3D) foam structure, which integrates porous structure, hierarchical property, excellent conductivity and high flexibility. The presence of CP(=O)(O)n (n ≤ 2) groups strengthens the linkage between Si nanoparticles, N-doped C and graphene. As an anode for lithium ion batteries, it delivers a stable discharge capacity of about 1130 mAh g−1 at 200 mA g−1. At 400 mA g−1, a discharge capacity of about 812 mAh g−1 is kept after 400 cycles with capacity retention of 83.5%, versus the second discharge capacity. At 3200 mA g−1, the composite exhibits a stable discharge capacity of about 480 mAh g−1 after 550 cycles. The excellent cycling performance and rate capability are ascribed to the improvement of conductivity, the enhancement of structural stability and the shortening of ion and electron diffusion pathways. As the coating layer of Si particles, the CP(=O)(O)n (n ≤ 2)-linked N-doped C exhibits obvious advantage over the C without CP(=O)(O)n groups in improving the cycling performance.Graphical abstractImage 1
       
  • Enhancing the interfacial interaction of carbon nanotubes fibers by Au
           nanoparticles with improved performance of the electrical and thermal
           conductivity
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Lin Qiu, Hanying Zou, Xiaotian Wang, Yanhui Feng, Xinxin Zhang, Jingna Zhao, Xiaohua Zhang, Qingwen Li The enhanced interfacial interaction between carbon nanotubes (CNTs), and thus the promoted interfacial thermal transport (ITT), are keys to improve the efficiency of CNT-assembled thermo-functional devices and materials, including energy transmission medium and thermal interface materials. Here, by using the intriguing CNT fibers decorated with Au nanoparticles (NPs) as a promising platform, we attain to the underlying mechanism for the remarkably boosted ITT of CNT/Au/CNT contacts. The enhancement is ascribed to the NP-induced excitation of low-frequency phonon (LFP) modes in CNTs, a strong mechanism to redistribute LFP modes into the interfacial carbon atoms and then to activate a resonance with the LFPs of Au NPs, resulting in more heat transfer across the contact. Furthermore, the Au NP/CNT fiber also exhibits an enhanced interfacial electrical transport, owing to the extraction of highly degenerate electronic density of states near the van Hove singularities, and thus induces an equivalent p-type doping for the CNTs. The present study demonstrates a new strategy to develop multifunctional CNT fibers with enhanced electrical and thermal conductivities.Graphical abstractImage 1
       
  • Fluorinated graphene provides long lasting ice inhibition in high humidity
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Naureen Akhtar, Gloria Anemone, Daniel Farias, Bodil Holst Ice formation on surfaces is a fascinating phenomenon with a major impact on a huge range of human activities from airplanes and shipping to wind mill parks, power transmission and telecommunication. A significant amount of work has been dedicated to the development of icephobic surfaces, often with the basis in superhydrophobicity. However, most surfaces investigated so far have not been very robust (an issue for operation in harsh and high humidity environments). Anti-icing strategies for practical applications in harsh environments have therefore mainly been related to the development of heatable coatings and/or mechanical removal or, in the case of airplanes, de-icing with glycol. Here we present a robust and lightweight anti-icing coating based on fluorinated graphene. The new coating delays ice formation for a striking 90 min at −15 °C up to 6 h and 45 min at −5 °C. All experiments were carried out at high humidity (50–55%). We also present first experiments of anti-icing on pure graphene. The very superior performance of the fluorinated graphene can be explained as a favourable combination of very low surface energy and nanoscale roughness.Graphical abstractImage 1
       
  • Effect of hydrogen peroxide on properties of graphene oxide in Hummers
           method
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Myung Jin Yoo, Ho Bum Park Among the several methods to prepare graphene oxide (GO) from graphite by oxidation, Hummers method has been the most widely used. Since Hummers method was first introduced about 60 years ago, many researches have tried to reveal the effect of each reagent on the final properties of GO. In all Hummers methods including the modified ones, sulfuric acid and potassium permanganate are used for oxidizing graphite and exfoliating oxidized graphite, and water and hydrogen peroxide are used for removing the residual manganese ions. However, the effects of hydrogen peroxide have been sometimes ignored during synthesis since hydrogen peroxide has been understood as simply reducing the residual manganese ions such as permanganate and manganese dioxide. For this reason, the quantity of hydrogen peroxide used for Hummers method varies. Here we demonstrate that the quantity of hydrogen peroxide added in the final stage strongly affects the final properties of GO. Experimental evidence is introduced revealing that chemical decomposition of GO with slight reduction accompanies the addition of hydrogen peroxide. The possible degradation mechanism by hydrogen peroxide in Hummers method is proposed in the last part of this study.Graphical abstractImage
       
  • Carbon nanotube- and graphene-based nanomaterials and applications in
           high-voltage supercapacitor: A review
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Zhoufei Yang, Jiarui Tian, Zefang Yin, Chaojie Cui, Weizhong Qian, Fei Wei The use of carbon nanotube- and graphene-based nanomaterials as a high-performance electrode is one of the promising directions when it comes to developing high-voltage supercapacitors with both a high power density and high energy density. However, the mass production and post-treatment of the carbon nanotube/graphene-based nanomaterials with high purity are necessary steps toward the commercialization of high-performance supercapacitors, and the challenges in engineering carbon nanotube/graphene-based nanomaterials for device-scale supercapacitors also need to be considered. In this review, the authors first introduce the chemical vapor deposition for large-scale preparation of carbon nanotube/graphene-based nanomaterials and the exfoliation method for graphene, which are followed by the methods used to purify these nanomaterials. Then, the capacitance performance of the carbon nanotube/graphene-based nanomaterials in the electrolytes of a high-voltage window is discussed, including the discussion of the capacitance limit of sp2 carbon materials, as well as a comparison of the capacitance performance in ionic liquids electrolytes with that in organic electrolytes and a discussion of low-temperature performance. Finally, the challenges in fabricating supercapacitor devices, such as the intake of excess liquids, the densification of carbon nanotube/graphene-based electrodes, and the reduction of the resistance of supercapacitors, are addressed.Graphical abstractThe use of carbon nanotube- and graphene-based nanomaterials as the high-performance electrode is supposed to be one of a promising direction to develop high-voltage supercapacitor with both high power density and high energy density. In this review, the chemical vapor deposition and the exfoliation methods for the large-scale preparation of carbon nanotube, graphene and their hybrids were reviewed, and the purification methods to remove metal impurities and oxygen-containing functional groups were introduced. Then the capacitance performance of the carbon nanotube/graphene-based nanomaterials in electrolytes of high voltage window was discussed, including the comparison with the organic electrolyte and the discussion of low-temperature performance. The methods in fabricating supercapacitor device including the intake of excess liquids, the densification of carbon nanotube/graphene-based electrode and the reduction of resistance of supercapacitor are also addressed.Image 1
       
  • Vertically edge-oriented graphene on plasma pyrolyzed cellulose fibers and
           demonstration of kilohertz high-frequency filtering electrical double
           layer capacitors
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Nazifah Islam, Md Nadim Ferdous Hoque, Wenyue Li, Shu Wang, Juliusz Warzywoda, Zhaoyang Fan High-frequency electrochemical capacitors or electrical double layer capacitor (HF-ECs) with large capacitance were developed from edge-oriented graphene (EOG) nanosheets perpendicularly grown around carbonized cellulose microfiber (CMF) sheets. Binder-free EOG/CMF electrodes were fabricated in a one-step 5-min plasma-enhanced chemical vapor deposition process, where cellulose fiber sheets were rapidly pyrolyzed by high-temperature plasma, while EOG simultaneously formed on the developing CMFs. Owing to combined unique characteristics of both EOG and CMF, such facilely produced electrodes exhibit excellent performance in terms of both high frequency response and high capacitance density. In aqueous electrolyte cells, 10 μm thick EOG/CMF electrode exhibits an areal capacitance of 1.07 mF cm−2 at 120 Hz along with a frequency of 13.8 kHz at −45° phase angle. ∼3 V organic electrolyte cells show an areal capacitance of 0.49 mF cm−2 at 120 Hz, and a frequency of 1.47 kHz at −45° phase angle. Developed HF-ECs were successfully applied in practical applications as ripple current filter in line-frequency AC/DC conversion, and as pulse power storage/smoother in environmental energy harvesting for self-powered micro devices.Graphical abstractImage 1
       
  • Prediction of a flexible anode material for Li/Na ion batteries:
           Phosphorous carbide monolayer (α-PC)
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Siyun Qi, Feng Li, Junru Wang, Yuanyuan Qu, Yanmei Yang, Weifeng Li, Mingwen Zhao High performance anode materials are crucial for the design and fabrication of alkali ion batteries. Here, using first-principles calculations, we demonstrate that the recently-synthesized phosphorous carbide monolayer (α-PC) is identified as an ideal flexible anode material for Li/Na ion batteries. Compared with other well documented anodes including graphene and phosphorene, α-PC has the advantages of strong adsorption affinity and fast diffusion channels for Li and Na ions. The theoretical storage capacity reaches 623.2 mAh g-1 for Li and 467.4 mAh g-1 for Na with a suitable open circuit voltage range. More importantly, α-PC is rather flexible along the direction crossing the grooves with elastic constant of only 13.1 GPa nm. Benefitted from the puckered structure, α-PC demonstrates a stable structure and suitable binding/diffusion energetics to Li/Na ions under a wide range of strain up to 21%. These unique features make α-PC an ideal anode material for the design and fabrication of future flexible batteries.Graphical abstractImage 1
       
  • Swift heavy-ion irradiation of graphene oxide: Localized reduction and
           formation of sp-hybridized carbon chains
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Andrzej Olejniczak, Nadezhda A. Nebogatikova, Aleksei V. Frolov, Miroslaw Kulik, Irina V. Antonova, Vladimir A. Skuratov Herein, we report the fabrication of nanometer-sized reduced graphene oxide (rGO) spots by swift heavy-ion (SHI) bombardment. Such structures can be considered graphene quantum dots (QDs) embedded in a non-conducting matrix. Both the number density and the diameter of the rGO spots can be tailored by a suitable choice of irradiation parameters (i.e., ion type, fluence, and energy). The degree of graphene oxide defunctionalization by SHIs with different energies scaled well with the deposited electronic energy density. The resistance of the samples decreased nonlinearly with increasing ion dose and, at fluences above 1013 ions/cm2, was orders of magnitude lower than the initial value. An increase in the electronic stopping power of the ion resulted (i) in suppression of the structural ordering at low fluences and (ii) in increased amorphization efficiency and formation of sp-hybridized carbon chains of both polyynes and polycumulenes at high fluences. A hypothesis suggesting that the sp-C chains are bridges joining opposite sides of nanoholes created inside the track core and thus assuming the formation of a coupled QD-antidot system is presented. These phenomena were found to be absent in comparative experiments with 200 keV Xe ion irradiation, i.e., in the nuclear stopping regime.Graphical abstractImage 1
       
  • Coining attributes of ultra-low concentration graphene oxide and spermine:
           An approach for high strength, anti-microbial and osteoconductive
           nanohybrid scaffold for bone tissue regeneration
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Sanjoy Kumar Ghorai, Somnath Maji, Bhuvaneshwaran Subramanian, Tapas Kumar Maiti, Santanu Chattopadhyay Lack of auto osteogenesis and clinical complexities of repairing of bone after severe injuries, urge to develop a significant approach to promote regeneration of bone. The present work represents ornamentation of 2D rod-like nanohydroxyapatite (nHA) on ultra-low concentration graphene oxide (GO) sheet. The nanohybrids (GO-nHA) were incorporated into the spermine based high strength thermoplastic polyurethane-urea (PUU) matrices by in situ technique and the porous scaffolds were fabricated. 1 wt% GO-nHA filled scaffold displayed dramatically improved physico-mechanical properties. Cytotoxicity study using osteoblast cell like MG-63 cell line revealed positive cell viability (above 95%) and increased proliferation over a period of 14 days of culture. Semi-quantitative Real Time polymerase Chain Reaction (qRT-PCR) showed positive expression of collagen type I and osteocalcin indicating excellent maturation and biomineralization of osteoblasts. To avoid burden of carbonaceous particulate in body, very low percentage of GO (0.15%) was incorporated into the scaffold to improve mechanical properties, surface wettability, cell viability and cell proliferation drastically. Furthermore, in vivo study confirmed the promoted osteogenesis of PUU/GO-nHA scaffold in vivo without any cytotoxicity. Based on mechanical, in vitro and in vivo study the high strength nanohybrid scaffold exhibited tremendous potential for orthopedic applications.Graphical abstractImage 1
       
  • Rectification effects of C3N nanoribbons-based Schottky
           junctions
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Congxin Xia, Lizhen Fang, Wenqi Xiong, Tianxing Wang, Shuyi Wei, Yu Jia Electronic and transport properties of semiconductor materials are very important to electronic and optoelectronic devices. Here, we present theoretical predication on the band structures and transport properties of zigzag C3N nanoribbons (ZC3NNRs) and related Schottky junctions. The results show that pristine ZC3NNRs are ferromagnetic metal, while the H-passivated ZC3NNRs are either nonmagnetic semiconductor or metal depending on their edge configurations. Interestingly, in the partitioned passivation-induced ZC3NNRs Schottky junction, the rectification ratio (∼105) is directly proportional to the channel length of H-passivated ZC3NNRs. For edge aligning-induced ZC3NNRs Schottky junction, the rectification ratio of aligning the CC_edge is about 25 times higher than that of aligning the CN_edge. These results may be useful to design two-dimensional (2D) materials-based Schottky junction electronic devices.Graphical abstractThe rectification ratio of C3NNRs-based Schottky junction depends on the channel length of semiconducting C3NNRs.Image
       
  • Buckling behaviors of metal nanowires encapsulating carbon nanotubes by
           considering surface/interface effects from a refined beam model
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Shuhong Dong, Chunhua Zhu, Yinfeng Chen, Junhua Zhao We develop a refined beam model to describe the buckling characteristics of hollow metal nanowires encapsulating carbon nanotubes (NWs@CNTs), where the interfacial van der Waals (vdW) interaction, interfacial shear stress as well as surface effect are taken into consideration. The analytical expressions for cohesive energies of the vdW interaction between carbon nanotubes (CNTs) and hollow nanowires are obtained through continuum modeling. The interfacial shear coefficients for NWs@CNTs with CNTs of different diameters and nanowires of different lattice orientations are derived by molecular dynamics simulations. The surface effects of nanowires are addressed by a function of the bulk surface energy density and surface relaxation parameter. The present results show that all the aforementioned three factors play key roles in the buckling behaviors of NWs@CNTs. In particular, the competition between CNTs and nanowires owing to the coupling effect of the three factors dominates their buckling patterns. This study may provide a theoretical support to prepare vertically aligned CNT arrays with nanoscale conformal coatings and to understand the stability and reliability of CNT reinforced composites.Graphical abstractImage
       
  • Dependence of characteristic interlayer vibration modes on interlayer spin
           arrangement in stacked graphene nanofragments
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Wanrun Jiang, Jia Wang, Rui Wang, Zhigang Wang The freedom of interlayer spin arrangement could emerge when assembling small-sized graphene-based nanostructures through stacking. Its possible influence on interlayer vibrations could be significant for developing Raman probes towards small complexes and device design involving intermolecular vibronic process. In this paper, using density-functional-theory calculations on bilayer and trilayer rhombic graphene fragments, we compare finite-size analogues to interlayer shear and breathing modes regarding to ferromagnetic and antiferromagnetic interlayer spin arrangements. For bilayer units, the antiferromagnetic configuration further separate two shear mode components by around 10 cm−1, inducing a further Raman peak splitting. This response is robust regarding to slightly enlarging the fragment and increasing layer number to three. Layer breathing mode is spin-arrangement robust in bilayers but show different arrangement-sensitivity in ABA-like and ABC-like trilayers. Visualization of interface electron density reveals the dependence of anisotropic interface environment to interlayer spin arrangement and unambiguously correlates the arrangement style with shearing responses. Further application of this analysis clarifies the arrangement-based phase-cooperation in trilayer shearing. Results and analysis in this work may contribute to the characterization and design of graphene-based nanostructures as well as understanding the interfacial nature beneath their intermolecular varieties in dynamic processes.Graphical abstractImage 1
       
  • Tuning the photoluminescence of graphene oxide quantum dots by
           photochemical fluorination
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Fuhua Gao, Fuchi Liu, Xiaohua Bai, Xiaofen Xu, Wenjie Kong, Jun Liu, Fengzhen Lv, Lizhen Long, Yong Yang, Ming Li Tailoring the band gap and understanding the underlying mechanism are important for extending the applications of graphene quantum dots in optoelectronics. In this work, we synthesize fluorinated graphene oxide quantum dots (F-GOQDs) through a photochemical method, and study their optical properties. The obtained F-GOQDs exhibit a maximal blue-shift of photoluminescence (PL) emission of ca. 77 nm compared to that of the graphene oxide quantum dots (GOQDs). The PL shift results from the substitution of the hydroxyls and carbonyls groups with fluorine during the fluorination process, which can tune the band gap of the GOQDs. Density functional theory (DFT) calculations support our proposed mechanism for band gap tuning in the GOQDs through the use of fluorination.Graphical abstractImage
       
  • Graphitization of 13C enriched fine-grained graphitic material under
           high-pressure annealing
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Yu.V. Fedoseeva, A.V. Okotrub, V.O. Koroteev, Yu.M. Borzdov, Yu. N. Palyanov, Yu.V. Shubin, E.A. Maksimovskiy, A.A. Makarova, W. Münchgesang, L.G. Bulusheva, A. Vyalikh Hot pressing is one of the promising routes for graphitization of carbon materials. In the present work, high-pressure high-temperature behaviour of 13C-enriched fine-grained graphitic material has been studied by using a set of experimental tools such as scanning electron microscopy, Raman scattering, X-ray diffraction, X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopies, and solid-state nuclear magnetic resonance (NMR) spectroscopy. The material has been annealed at a temperature of 1200 or 1500 °C using a stabilizing pressure of 5 GPa. It shown, that addition of small amount of water during the annealing at 1200 °C results in a better local atomic ordering of carbon material and increases the hydrocarbon fraction. Well-ordered graphite crystals enriched with 13C isotope are formed on the surface of nickel ampule at 1500 °C. An increase in processing time from 2 to 15 h decreases the defect density and improves the graphitization level of the material.Graphical abstractImage 1
       
  • Pattern evolution characterizes the mechanism and efficiency of CVD
           graphene growth
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Wanzhen He, Dechao Geng, Zhiping Xu Growing large-area, high-quality monolayers is the holy grail of graphene synthesis. In this work, the efficiency of graphene growth and the quality of their continuous films are explored through the time evolution of individual domains and their surface coverage on the substrate. Our phase-field modeling results and experimental characterization clearly demonstrate the critical roles of the deposition flux, edge-reaction kinetics and the surface diffusion of active carbon sources in modulating the pattern evolution and rate of growth. We find that the contrast between the edge-kinetics-limited and surface-diffusion-limited regimes is remarkable, which can be characterized by the evolution of domain patterns and considered as an indicator of the growth regime. However, common features exist in these two regimes, showing that the growth rate scales with time as t2 in the early stage of growth and is regime-independent, which is explained by the coarsen profiles of carbon concentration for both the compact and dendritic domains. The rate decays rapidly in the final stage of growth due to the competition between neighboring domains on the limited carbon sources diffusing on the substrate, which is highly regime-sensitive and extremely low in the surface-diffusion-limited regime with narrow gaps between the domains to be filled. Based on these findings, synthesis strategies to improve the growth efficiency and film quality are discussed.Graphical abstractImage 1
       
  • Modeling the effects of oxidation-induced porosity on the elastic moduli
           of nuclear graphites
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Lauren R. Olasov, Fan W. Zeng, James B. Spicer, Nidia C. Gallego, Cristian I. Contescu Oxidation of nuclear graphites produces microstructural changes that affect the elastic moduli of these materials. It is widely accepted that the primary effect of oxidation is to increase porosity, but the related effect on the moduli cannot be explained satisfactorily by simply noting changes to porosity. In this work, models describing the elastic moduli of porous, polycrystalline graphite materials are developed to interpret experimental determinations of Young's modulus and shear modulus in two grades of nuclear graphite – IG-110 and NBG-18 – that were oxidized to produce varying levels of porosity. Experimental measurements were carried out using laser-based ultrasonic methods and were interpreted successfully using models that take into account the effects of preferential oxidation of different elements of the graphite microstructure. The results indicate the importance of the processes that lead to increased porosity since these can heavily influence the nature of the resulting structure-property relationships.Graphical abstractImage 1
       
  • N-, P-, As-triphenylene-graphdiyne: Strong and stable 2D semiconductors
           with outstanding capacities as anodes for Li-ion batteries
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Bohayra Mortazavi, Masoud Shahrokhi, Mohamed E. Madjet, Meysam Makaremi, Said Ahzi, Timon Rabczuk Since the first report of graphdiyne nanomembranes synthesis in 2010, different novel graphdiyne nanosheets have been fabricated. In a latest experimental advance, triphenylene-graphdiyne (TpG), a novel two-dimensional (2D) material was fabricated using the liquid/liquid interfacial method. In this study, we employed extensive first-principles simulations to investigate the mechanical/failure, thermal stability, electronic and optical properties of single-layer TpG. In addition, we predicted and explored the properties of nitrogenated-, phosphorated- and arsenicated-TpG monolayers. Our results reveal that TpG, N-TpG, P-TpG and As-TpG nanosheets can exhibit outstanding thermal stability. These nanomembranes moreover were found to yield linear elasticity with considerable tensile strengths. Notably, it was predicted that monolayer TpG, As-TpG, P-TpG and N-TpG show semiconducting electronic characters with direct band-gaps of 1.94 eV, 0.88 eV, 1.54 eV and 1.91 eV, respectively, along with highly attractive optical properties. We particularly analyzed the application prospect of these novel 2D materials as anodes for Li-ion batteries. Remarkably, P-TpG and N-TpG nanosheets were predicted to yield ultrahigh charge capacities of 1979 mAh/g and 2664 mAh/g, respectively, for Li-ions storage. The acquired results by this work suggest TpG based nanomembranes as highly promising candidates for the design of flexible nanoelectronics and energy storage devices.Graphical abstractImage 1
       
  • On the piezoresistive behavior of carbon fibers - Cantilever-based testing
           method and Maxwell-Garnett effective medium theory modeling
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Yanbo Yao, Jiangjiang Luo, Xiaoshuang Duan, Tao Liu, Yonggang Zhang, Baihua Liu, Muhuo Yu A good understanding of the piezoresistive behavior of carbon fiber is highly valuable in studying the processing-structure-property relationship of this very important engineering material. Up-to-date, there is still a lack of agreement on the physical origin of the unique modulus-dependent piezoresistivity for carbon fibers. In the present work, an experimental and theoretical modeling combined approach was taken to attack this long outstanding issue. A cantilever testing method was developed which allows for the evaluation of the piezoresistive behavior of a single carbon fiber filament under axial tension and compression mode. It was found that the tensile and compressive piezoresistive behavior showed antisymmetric characteristics. This supports the concept that the orientation of the basic structural units (BSUs) is responsible for the piezoresistivity of carbon fibers. Such an argument was further augmented by theoretical modeling of the carbon fiber piezoresistivity based on a Maxwell Garnett theory approach. The new piezoresistivity model identifies the critical role of the compound effect of the BSU orientation and its volume fraction in dictating the piezoresistive behavior of carbon fibers. With consideration of this compound effect, the modulus-dependent piezoresistivity data of carbon fibers reported in the past few decades can now be well explained.Graphical abstractImage 1
       
  • Mapping the stacking interaction of triphenyl vinylene oligomers with
           graphene and carbon nanotubes
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): A. Yaya, A. Impellizzeri, F. Massuyeau, J.L. Duvail, P. Briddon, C.P. Ewels Using density functional calculations, we explore π-π and π-H stacking interactions in conjugated polymer – carbon nanomaterial composites, through a detailed surface energy mapping procedure. Taking the triphenyl vinylene oligomer as a structural model for poly para-phenylene vinylene (PPV), we map intermolecular stacking configurations between PPV pairs. We then map PPV translation over the surface of graphene, and explore orientation dependence in PPV-nanotube interaction with tubes of different chirality and diameter. Preferential stacking orientations are shown, and commensurability between the polymer and carbon substrate is demonstrated. Conjugated polymers such as PPV lie at the crossroads between small organic molecules such as benzene and extended conjugated carbon systems such as graphene. With the current calculations we are able to reconcile the range of stacking behaviours seen in these diverse materials, with literature experimental polarized Raman spectroscopy results.Graphical abstractImage 1
       
  • Graphene as an electrochemical transfer layer
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Tiva Sharifi, Yu Xie, Xiang Zhang, Hamid Reza Barzegar, Jincheng Lei, Gabriel Coulter, Shiyun Sun, Chandrasekhar Tiwary, Alex Zettl, Boris Yakobson, Pulickel M. Ajayan The capability of graphene to adopt a property from an adjacent material is investigated by measuring the electrochemical performance of a monolayer graphene placed on top of thin cobalt oxide (Co3O4) nanosheets. In this assembly, monolayer graphene works as an interfacial layer which inhibits the direct contact of the actual electroactive material and electrolyte during electrochemical reaction. The results show that while graphene is electrochemically inert, it behaves as an active material to catalyze oxygen evolution reaction (OER) once placed on top of Co3O4 nanosheets. The graphene-covered Co3O4 model system shows electrochemical performance similar to Co3O4 indicating complete transference of the electrochemical property of the metal oxide to the graphene. Based on density functional theory (DFT) calculations, charge transfer from graphene to Co3O4 is the key factor for turning the electrochemically inactive graphene to an apparent active material.Graphical abstractImage 1
       
  • ZnO nanoparticles filled tetrapod-shaped carbon shell for lithium-sulfur
           batteries
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Rongliang Yang, Huiwei Du, Zhiqiang Lin, Leilei Yang, Hai Zhu, Hao Zhang, Zikang Tang, Xuchun Gui Employ of hollow nanostructure carbon materials as a host framework for sulfur cathode is a promising strategy to cope with the notorious posers in lithium-sulfur (LiS) battery. However, the dissolution and diffusion of intermediate polysulfides in electrolytes still result in rapid capacity loss and poor rate performances, due to the weak interaction between polarized lithium polysulfides and non-polarized carbon host. To address this challenge, a bipolar material, zinc oxide embedded tetrapod-shaped carbon shell (TCS/ZnO) is designed for polysulfides immobilization in LiS battery. The TCS/ZnO composites are synthesized through a CVD process using tetrapod shaped ZnO nanowhiskers as template, following by a partially hydrogen etching treatment. Attributed to the strong chemisorption of ZnO to polysulfides, high initial specific capacity of 1284 mAh g−1sulfur, stable Coulombic efficiency of ∼99.5% and excellent cycling stability (815 mAh g−1sulfur after 100 cycles at 0.2 C) are exhibited for S-TCS/ZnO cathode with optimized ratio of ZnO.Graphical abstractImage 1
       
  • Manipulating graphene kinks through positive and negative radiation
           pressure effects
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): R.D. Yamaletdinov, T. Romańczukiewicz, Y.V. Pershin We introduce an idea of experimental verification of the counterintuitive negative radiation pressure effect in some classical field theories by means of buckled graphene. In this effect, a monochromatic plane wave interacting with topological solutions pulls these solutions towards the source of radiation. Using extensive molecular dynamics simulations, we investigate the traveling wave-induced motion of kinks in buckled graphene nanoribbons. It is shown that depending on the driving source frequency, amplitude and direction, the kink behavior varies from attraction to repulsion (the negative and positive radiation pressure effects, respectively). Some preliminary explanations are proposed based on the analogy to certain field theory models. Our findings open the way to a new approach to motion control on the nanoscale.
       
  • Three-dimensional honeycomb carbon: Junction line distortion and novel
           emergent fermions
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Junping Hu, Weikang Wu, Chengyong Zhong, Ning Liu, Chuying Ouyang, Hui Ying Yang, Shengyuan A. Yang Carbon enjoys a vast number of allotropic forms, each possessing unique properties determined by the lattice structures and bonding characters. Here, based on first-principles calculations, we propose a new three-dimensional carbon allotrope—hC28. We show that hC28 possesses excellent energetic, dynamical, thermal, and mechanical stability. It is energetically more stable than most other synthesized or proposed carbon allotropes. The material has a relatively small bulk modulus, but is thermally stable at temperatures as high as 2000 K. The structural, mechanical, X-ray diffraction, and electronic properties are systematically investigated. Particularly, we show that its low-energy band structure hosts multiple unconventional emergent fermions, including the quadratic-contact-point fermions, the birefringent Dirac fermions, and the triple-point fermions. We construct effective models to characterize each kind of fermions. Our work not only discovers a new carbon allotropic form, it also reveals remarkable mechanical and electronic properties for this new material, which may pave the way towards both fundamental studies as well as practical applications.Graphical abstractImage 1
       
  • Advanced nanostructured carbon-based materials for rechargeable
           lithium-sulfur batteries
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Linlin Zhang, Yijing Wang, Zhiqiang Niu, Jun Chen Lithium-sulfur (Li-S) batteries are attracting much attention due to their high energy densities. However, Li-S batteries often suffer from low Coulombic efficiency, severe degradation of cyclic capacity, and low utilization of active sulfur material because of the low electrical conductivity of sulfur and the severe shuttle effect. To solve these issues, various nanostructured carbon-based materials have been developed to serve as the sulfur host materials, modify separators and protect lithium (Li) anode due to their good conductivity, large surface area, and electrochemical stability. In this review, a brief introduction of electrochemical principles and prospects of the Li-S batteries are discussed firstly. Then the recent achievements and challenges of nanostructured carbon-based materials in Li-S batteries are summarized. The nanostructured carbon-based materials focus on active carbon, carbon nanotubes, graphene and their composites. The role of these carbon-based materials in Li-S batteries emphasize on the design of sulfur host materials, the modification of functional separators as well as the protection of the Li anode. Furthermore, various flexible Li-S batteries based on freestanding nanostructured carbon/sulfur electrodes are also presented. Finally, the further developments and prospects in this field are also discussed.Graphical abstractImage
       
  • The carbon substrate in RST Si ribbon technology for solar cells
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): C. Belouet, M. Monville, C. Bigot, E. Jolivet, R. Varrot, J. Chancolon, S. Bonnamy The carbon substrate used in the RST (silicon Ribbon growth on a Sacrificial carbon Template) process, a silicon ribbon growth technology aimed at the fabrication of silicon solar cells, is a composite made of a compressed expanded natural graphite (CENG) ribbon coated by a protective rough lamellar high-temperature (RLHT) pyrocarbon. It is shown that the reactivity of RLHT pyrocarbon with molten silicon is stimulated by the presence of topological defects of the CENG ribbon. This reactivity generates a contamination of the silicon melt by carbon and its metallic impurities and, in turn, adversely affects the performances of solar cells made from RST silicon films. Reactivity with molten silicon can be drastically reduced by the control of the deposition conditions of pyrocarbon and of the roughness of the CENG ribbon. A new model is proposed to explain the mechanism of the intrinsic reactivity of RLHT pyrocarbon with molten silicon. Based on this model the reactivity problem can virtually be eliminated by the deposition of a SiC coating about 0.3 μm on the RLHT pyrocarbon. Improvements of the carbon ribbon, described in this study, especially its pyrocarbon coating, should lead to flexible silicon solar cells 70–80 μm thick with conversion efficiency above 18%.Graphical abstractImage 1
       
  • Terahertz biosensing with a graphene-metamaterial heterostructure platform
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Wendao Xu, Lijuan Xie, Jianfei Zhu, Longhua Tang, Ranjan Singh, Chen Wang, Yungui Ma, Hou-Tong Chen, Yibin Ying Terahertz (THz) radiation attracted great interest in the fields of material characterization, nondestructive security screening, clinical diagnostics, and identification of chemicals and molecules. Label-free THz sensing of trace amount of targets including biomolecules is promising because of their rich spectral fingerprint in this electromagnetic region; however, improving the sensitivity remains to be a challenge, partially due to the limitations of THz sources and detectors. The resonantly enhanced electromagnetic fields in metamaterials and metasurfaces offer a potentially viable solution, although highly complicated decoration process is still needed for biosensing on the surface of metamaterials. Here we demonstrate a simple biosensing platform by integrating a monolayer graphene on a THz metamaterial absorber cavity, where the introduction of sensing targets results in a large change of the metamaterial resonant absorption (or reflection) because of their strong interaction with graphene. We experimentally show its ultrahigh sensitivity through detecting trace amount of chlorpyrifos methyl down to 0.2 ng. Using simple decoration steps and utilizing DNA to capture thrombin, we further show the feasibility of this platform serving as a sensitive biosensor.Graphical abstractImage 1
       
  • Nanoparticle intercalation-modulated stretchable conductive graphene
           fibers with combined photoelectric properties
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Zhengpeng Yang, Yutao Niu, Wei Zhao, Yongyi Zhang, Hao Zhang, Chunjing Zhang, Wujun Zhang, Xi Xiang, Qingwen Li Graphene fiber with superb properties poses an important role in future functional fibers and devices. However, the fibers made of neat graphene sheets remain brittle and the electrical conductivity of graphene/polymer fibers is very poor, which all together hiders wide use of graphene fibers. It remains a big challenge to obtain functional graphene fibers with combined electrical and mechanical properties. Here, we demonstrate a simple wet spinning of stretchable conductive graphene fibers through uniform intercalation of TiO2 nanoparticles between graphene sheets. The TiO2 nanoparticles induce formation of numerous winkles on graphene sheets which all together makes the composite fibers show combined superb mechanical, electrical and photoelectric performances. With increasing of TiO2 from 0 to 50%, the fibers still have comparable electrical conductivities, while the breakage elongation greatly increases from less than 6% to higher than 20%, and the fibers with 50% TiO2 have excellent tensile recovery within 15% strain. With TiO2 combined, the fibers have extra functional properties in photoelectric response, which can be further improved by oxygen plasma etching, and no obvious decay is observed even after 100 bending cycles. This study provides useful guidelines for designing of functional conductive graphene fibers with highly stretchable performance towards future uses.Graphical abstractStretchable conductive graphene fibers with highly wrinkled architecture, which are fabricated by the uniform intercalation of TiO2 nanoparticles between graphene sheets via a simple wet spinning technique, show high breaking elongation and excellent photoelectric properties.Image 1
       
  • Mapping temperature and confinement dependence of carbyne formation within
           carbon nanotubes
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Yichen Deng, Steven W. Cranford Single atomistic chains of carbon – a.k.a. carbyne – are of great interest due to their attractive properties. One route of proposed synthesis is exploiting the interior of a carbon nanotube, enabling sufficient alignment and affable temperature conditions for chain growth. Here, we delineate the optimal conditions for growth by means of full atomistic modeling of sequential carbon reactions inside single walled carbon nanotubes (SWCNTs). Seeding the interior of a SWCNT with free carbons, we vary the nanotube diameters and temperature, and compare the resulting chain lengths. We systematically study the affecting factors of carbyne synthesis, investigating the effects of temperature, confinement (via nanotube diameter) and alignment (using polymer shape metrics). We verify with prior experimental studies that carbyne can be successfully synthesized when the inner diameter is less than approximately 9 Å and temperature is higher than 500 K. Additionally, we map the chain length with respect to the nanotube diameter and the temperature and propose a simple empirical/phenomenological relation to predict growth rate based on classical collision theory with a modified Arrhenius relation.Graphical abstractImage 1
       
  • Competitive or additive behavior for H2O and CO2 gasification of coal
           char' Exploration via simplistic atomistic simulation
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Yongbo Du, Chang'an Wang, Haihui Xin, Defu Che, Jonathan P. Mathews Here, a large-scale char atomistic structure (41,438 carbon atoms) and simple simulation approaches explored char gasification behavior for H2O and CO2 — comparing their mixture with one gas being passive (non-reactive) and the dual reactive mixture. Reactivity was captured through simplistic atomistic simulations via an automated sequence of gas diffusion, close-contact determination for gas (es) to reactive edge sites, then “reaction” via atom deletion. The higher reactivity of H2O was captured by a reaction probability function. For the reactive mixture (where both gases are reactive), the char consumption rate was 14% higher than with H2O alone, but lower (∼80%) than the sum of the individual gases (where only one gas is reactive), demonstrating competitive behavior. The H2O out competed the CO2 molecules and contributed ∼83% to the char consumption — with the reaction rate being similar to that of H2O independently. The pore size development for individual gases also differed with H2O favoring development in the smaller pore sizes in comparison to CO2. With fewer gas molecules (using 10% to capture a lower pressure), the competitive behavior was muted and became much closer to additive behavior. These simple simulations are consistent with the emerging rationalization of contributing factors to char gasification.Graphical abstractImage 1
       
  • New insights into structural evolution in carbon molecular sieve membranes
           during pyrolysis
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Jason S. Adams, Arun K. Itta, Chen Zhang, Graham B. Wenz, Oishi Sanyal, William J. Koros Carbon molecular sieve (CMS) membranes separate penetrants using size and shape-selective pores. In this paper we report pyrolysis of a 6FDA:BPDA-DAM polyimide precursor between 500 and 800 °C and measure gas evolution during the CMS structural development. The CMS materials were then characterized using combined transport properties, porosimetry, FTIR, Raman spectroscopy, TGA-FTIR, WAXD, and elemental analysis measurements to assess their resulting physical and chemical properties. The results support a previous vision that fragmentation of the polyimide precursor occurs to form aromatic strands that provide building blocks for the overall CMS cell structure. This fact notwithstanding, these new findings indicate that constituent strands appear to be more complicated than previously suggested. An ordering process of such strands can generate a bimodal morphology comprising larger micropores with irregular cell walls containing ultramicropores. Permeability and permselectivity of the CMS for the C2H4/C2H6 pair are also correlated with CMS structures based on the above characterizations. The results of this work suggest that molecular probe-based transport measurements are by far the most useful tools to study these complex, amorphous materials for molecular separation applications.Graphical abstractImage 1
       
  • High ampacity of superhelix graphene/copper nanocomposite wires by a
           synergistic growth-twisting-drawing strategy
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Kai Zhao, Tengfei Zhang, Ai Ren, Yang Yang, Peishuang Xiao, Zhen Ge, Yanfeng Ma, Yongsheng Chen Nanocarbon materials can provide effective reinforcement to a surrounding composite matrix. However, the fabrication of nanocarbon/metal composites with superior comprehensive properties remains challenging. Here, we developed a simple cyclic growth-twisting-drawing method to fabricate superhelix graphene/copper nanocomposite wires composed of massive, strongly bonded, and super-helically arranged fine copper fibers with interfacial graphene layers. The obtained nanocomposite wires with a small graphene volume fraction of ∼0.32% exhibit a largely improved current carrying capacity of 5.8 × 1010 A m−2, ∼2.6 times of that of pure copper wires. Furthermore, the electrical conductivity, 5.01 × 107 S m−1, is comparable to that of pure copper. These nanocomposite wires also exhibit improved strength and ductility, 10% and 80% increases compared with that of pure copper wires. These multiple enhanced properties can be attributed to the microscopic superhelix structure with the interfacial graphene layers embedded in the entire multi-level structure. With their largely improved current carrying capacity and mechanical reinforcement, these highly electrically conductive nanocomposite wires promise widely potential applications in the areas of heavy duty, high power electronics and electricity transmission.Graphical abstractImage 1
       
  • Peering into the structural evolution of glass-like carbons derived from
           phenolic resin by combining small-angle neutron scattering with an
           advanced evaluation method for wide-angle X-ray scattering
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): F. Badaczewski, M.O. Loeh, T. Pfaff, S. Dobrotka, D. Wallacher, D. Clemens, J. Metz, B.M. Smarsly The structural evolution of two non-graphitizing glass-like carbons derived from a liquid resole and a solid novolac-type phenolic resin was quantitatively characterized by combining small-angle neutron scattering (SANS) with an advanced evaluation for wide-angle X-ray scattering (WAXS) data. Utilizing these two methods allowed for studying the microstructure on the Ångstrom level (graphene stacks, WAXS) and the inaccessible microporosity (SANS). The applied WAXS analysis provided quantitative structural parameters for both, size and disorder in the polyaromatic sp2 microstructure. Hence, the combined SANS-WAXS analysis yielded comprehensive insights into the relation between the graphene microstructure and the inaccessible porosity upon heat treatment for glass-like carbons, i.e. a non-graphitizing class of carbon. In particular, the analogue investigation of a graphitizing mesophase pitch demonstrates the major impact of the chemical composition of the utilized carbon precursor. For the glass-like carbons the results revealed different growth rates for the lateral extent of the basic structural units (La) depending on the temperature range, finally reaching 12 nm, whereas the stack height (Lc) exhibiting 2.2 nm is hardly affected by the thermal processing up to 3000 °C. As a major finding our study thus relates the evolution of microstructure and porosity to changes in chemical composition.Graphical abstractImage 1
       
  • Bio-inspired graphene-based coatings on Mg alloy surfaces and their
           integrations of anti-corrosive/wearable performances
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): J.H. Chu, L.B. Tong, J.B. Zhang, S. Kamado, Z.H. Jiang, H.J. Zhang, G.X. Sun Mg and its alloys generally exhibit the poor corrosion and wear resistances, which greatly limits their industrial applications. Inspired from an ordered layered structure within natural nacre, the homogeneous reduced graphene oxide/poly (vinyl alcohol) (RGO/PVA) coating is successfully fabricated on Mg alloy surface in the current study, through a facile spin-assisted layer-by-layer assembly (SA-LBL) technology. The hybrid hydrogen/covalent bond networks form between PVA chains and RGO sheets, resulting in a compact lamellar “bricks-and-mortar” structure. The microstructure of hybrid coating is strongly influenced by the cross-linking effect of PVA molecule, whose suitable content is beneficial to generating the densely stacked lamellar coating with excellent binding strength and reduced intrinsic defects, which can significantly improve its corrosion resistance. And the water molecules can hardly diffuse into the hybrid coating, leading to a long-term stability of samples in aqueous solution, ethanol and N, N-dimethylformamide. Besides, the high hardness and good lubricant effect of RGO sheets confer the hybrid coatings outstanding wear-resistant properties. Therefore, the bio-inspired RGO coating with a certain amount of PVA allows it to have a superior barrier effect and maintain the lubrication, which can provide an integrated protection for the corrosion and wear behaviors of Mg alloy.Graphical abstractImage
       
  • Unique thermal contraction of zeolite-templated carbons enabling micropore
           size tailoring and its effects on methane storage
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Seokin Choi, Mustafa A. Alkhabbaz, Yuguo Wang, Rashid M. Othman, Minkee Choi Zeolite-templated carbons (ZTCs) were prepared by the carbon replication of two different zeolite structures, i.e., BEA and FAU. We demonstrated that the micropore size of the ZTCs could be systematically controlled via post-synthesis thermal contraction. The thermal contraction was the unique feature of ZTCs, which was not observed with conventional activated carbons. The ZTCs had extra-high H contents on the abundant carbon edge sites because of their 3-dimensionally connected graphene nanoribbon structure. Thermal treatment in the absence of zeolite templates induced further dehydrogenation and densification of carbon framework, which caused such structural contraction. The ZTCs with tailored micropore sizes (1.1–1.5 nm) were used to study the effects of microporous structures on CH4 adsorption. Notably, the ZTCs with micropores smaller than 1.3 nm showed abnormal increases in the isosteric heat of adsorption with increasing CH4 coverage. This strongly indicated the presence of substantial lateral interactions between the adsorbates within these uniform micropores. The ZTC prepared from BEA zeolite and subsequently treated at 873 K showed the most promising volumetric CH4 storage capacity (210 cm3STP cm−3) and working capacity (175 cm3STP cm−3) at 5–65 bar due to its optimum microporous structures and uniform particle morphology enabling efficient particle packing.Graphical abstractImage 1
       
  • Pseudocapacitive Co9S8/graphene electrode for
           high-rate hybrid supercapacitors
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Bingqiao Xie, Mengying Yu, Luhua Lu, Huazhang Feng, Yang Yang, Ying Chen, Hongda Cui, Rubo Xiao, Jian Liu Cobalt pentlandite (Co9S8) has recently emerged as a promising electrode material for energy storage devices. Herein, Co9S8/graphene hybrid is rationally synthesized through a facile hydrothermal method. Minor-sized Co9S8 flakes is finely-deposited on the surface of graphene sheet and an interconnected Co9S8/graphene architecture structure is obtained. The electrochemical test results show that Co9S8/graphene electrode delivers a remarkable charge capacity of 540 C g−1 within 1 min and 74.5% capacitance is retained within a discharge time of 14 s. A hybrid supercapacitor assembled with Co9S8-involved electrode delivers a high energy density of 37 Wh kg−1 at a power density of 170 W kg−1, and 15.3 Wh kg−1 can be maintained even at a high power density of 12 kW kg−1. The excellent electrochemical performance should be attributed to abundant active sites, enhanced charge-transfer characters and maximized capacitive contribution of Co9S8/graphene electrode.Graphical abstractCross-linked and robust Co9S8/graphene (CoSG) hybrid electrode with remarkable pseudocapacitive features was designed for high-rate hybrid supercapacitors(HSCs).Image 1
       
  • Phonon anharmonicities in supported graphene
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Egor A. Kolesov, Mikhail S. Tivanov, Olga V. Korolik, Olesya O. Kapitanova, Hak Dong Cho, Tae Won Kang, Gennady N. Panin The paper presents temperature-dependent Raman studies of anharmonic phonon properties of graphene as-grown on copper, transferred to copper, SiO2/Si, and Al2O3, as well as nitrogen-doped graphene on SiO2/Si. Different G and 2D peak position and linewidth temperature dependencies were obtained in the temperature range of 20–294 K, upon which anharmonic constants for 3- and 4-phonon processes were determined. Values of anharmonic constants obtained from G peak shift for undoped graphene on dielectric substrates were quantitatively close to both experimental results for unsupported graphene and theoretical predictions reported in the literature, while the values for graphene as-grown on copper were almost two orders of magnitude greater. The results were analyzed in terms of substrate effect on phonon properties of graphene. The present study is useful for taking into account anharmonic phonon effects in graphene when designing graphene-based nanoelectronic devices.Graphical abstractImage
       
  • Influence of hydrogen and halogen adsorption on the photocatalytic water
           splitting activity of C2N monolayer: A first-principles study
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): M.R. Ashwin Kishore, Anja Olafsen Sjåstad, P. Ravindran Adsorption of impurity atoms or molecules on the surface of photocatalysts may improve or worsen the photocatalytic activity due to chemical bond relaxations. Herein, we demonstrate the influence of molecular adsorbates such as H2, F2, Cl2, Br2, and I2 on the electronic properties and photocatalytic activity of the nitrogenated holey graphene (C2N) using hybrid density functional calculations including van der Waals interaction. Hydrogen and halogen molecules prefer to physisorb on the holey site except F2 which has substantial chemisorption. The halogens tend to draw electrons from C2N monolayer due to their high electronegativity and thereby introduce new band states which significantly alters the opto-electronic and photocatalytic properties. Although F2 and Br2 adsorbed C2N have favorable band edge positions, I2 adsorbed C2N is more promising for hydrogen production because of its appropriate band edge positions relative to the water redox potentials. Optical absorption spectra reveals that all these systems are visible light active and therefore they could harvest more incoming light. We have demonstrated here for the first time that intermediate bandgap states can be introduced in C2N system by adsorbing halogen molecules and our theoretical findings suggest that I2 adsorbed C2N monolayer is a promising candidate for photocatalytic water splitting.Graphical abstractImage 1
       
  • Tribological and mechanical properties of graphene nanoplatelet/PEEK
           composites
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): J.A. Puértolas, M. Castro, J.A. Morris, R. Ríos, A. Ansón-Casaos Poly(ether ether ketone) (PEEK) is a relevant thermoplastic in industry and in the biomedical sector. In this work, the lubricant capability of graphene nanoplatelets (GNPs) is used for improving the PEEK wear properties. Nanocomposites were prepared by solvent-free melt-blending and injection molding at various compositions between 1 and 10 wt. % of GNPs. The Raman G band shows a progressive increment proportional to the bulk GNP percentage. From calorimetric data, the polymer matrix structure is interpreted in terms of a 3-phase model, in which the crystalline phase fluctuates from 39 to 34% upon GNP addition. Thermal conductivity varies in accordance with the polymer crystallinity. Tensile and flexural tests show a progressive increase in the modulus, as well as a decrease in the fracture strength and the work of fracture. Most important, the composite surface undergoes a substantial improvement in hardness (60%), together with a decrease in the coefficient of friction (−38%) and a great reduction in the wear factor (−83%). Abrasion and fatigue wear mechanisms are predominant at the lowest and highest GNP concentrations respectively. In conclusion, GNPs are used without any chemical functionalization as the filler in PEEK-based materials, improving the surface hardness and the tribological properties.Graphical abstractImage 1
       
  • Tuning the sub-processes in laser reduction of graphene oxide by adjusting
           the power and scanning speed of laser
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Zhengfen Wan, Shujun Wang, Ben Haylock, Jasreet Kaur, Philip Tanner, David Thiel, Robert Sang, Ivan S. Cole, Xiangping Li, Mirko Lobino, Qin Li Laser reduction of graphene oxide is a promising technology for manufacturing advanced devices such as supercapacitors, sensors and transistors, owing to its distinctive advantages in selective and localized GO reduction, direct micro-nanoscale patterning, and no requirement for chemicals. However, the fundamental mechanism underlying the laser induced reduction is still not well understood. In this paper, we demonstrate that by adjusting the power and scanning speed of a 780 nm femtosecond laser, not only can one distinguish, but also effectively tune, two coexisting sub-processes during the laser reduction, namely the direct conversion from sp3 to sp2 carbon and removal of oxygen functional groups. Different oxygen containing groups demonstrate varied degrees of reduction when the power of the laser was varied. Our study provides solid and direct evidence for the coexistence of two sub-processes in the laser induced reduction of graphene oxide, which is essential for both mechanistic understanding and practical adoption of this technique in real word applications.Graphical abstractImage 1
       
  • Growth and Raman spectroscopy of thickness-controlled rotationally faulted
           multilayer graphene
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): H. Kato, N. Itagaki, H.J. Im We report the growth of thickness-controlled rotationally faulted multilayer graphene (rf-MLG) on Ni foils by low-pressure chemical vapor deposition and their characterization by micro-Raman spectroscopy. The surface morphology and thickness were investigated by scanning electron microscopy, X-ray diffraction, and transmittance measurements. These results have revealed that the thickness of rf-MLG can be effectively controlled by the thickness of the Ni foil rather than the flow rate of CH4, H2, Ar. In Raman spectroscopy measurements, we observed most Raman peaks of the graphitic materials. Raman spectra can be categorized into four patterns and show systematic behaviors. Especially, the in-plane (∼1880 cm−1, ∼2035 cm−1) and out-of-plane (∼1750 cm−1) modes are successfully analyzed to explain the dimensionality of rf-MLG as in the twisted (or rotated) bilayer graphene. In addition, it is found that the two peaks at ∼1230 cm−1 and ∼2220 cm−1 well reflect the properties of the in-plane mode. The peak intensities of the above four in-plane modes are proportional to that of 2D band, indicating that they share the common Raman resonance process.Graphical abstractImage 1
       
  • In situ formation of uniformly dispersed Al4C3 nanorods during additive
           manufacturing of graphene oxide/Al mixed powders
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Weiwei Zhou, Mingqi Dong, Zhengxin Zhou, Xiaohao Sun, Keiko Kikuchi, Naoyuki Nomura, Akira Kawasaki A novel Al4C3 nanorod was synthesized through an in situ reaction between graphene oxide (GO) and Al powders during laser powder bed fusion (L-PBF). The few-layer GO sheets were prepared by a modified Hummers method and were mixed with Al powders by electrostatic self-assembly. After subsequent L-PBF processing, the GO reacted with Al atoms completely to form Al4C3 nanorods that had a mean diameter of ∼140 nm and length of ∼2.3 μm, displaying a higher aspect ratio than that made by traditional powder metallurgy. Observations of high-resolution transmission electron microscopy revealed that the Al4C3 was monocrystalline and intimately contacted with the Al matrix, consequently resulting in the noticeably enhanced mechanical performance of the composite. This work may offer significant guidance for designing and producing new high-specific-strength materials for structural applications.Graphical abstractImage 1
       
  • Nanoscale reduction of resistivity and charge trap activities induced by
           carbon nanotubes embedded in metal thin films
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Narae Shin, Jeongsu Kim, Shashank Shekhar, Myungjae Yang, Seunghun Hong We mapped the nanoscale reduction of resistivity and noise source activities induced by metallic single walled carbon nanotubes (m-SWCNTs) embedded in gold thin films. In this method, current and noise maps of m-SWCNTs/gold hybrid thin films were recorded using a conducting probe in contact with the surface, and the maps were utilized to estimate the nanoscale variation of resistivity (ρ) and the density distribution of noise sources (Neff) generating electrical noises in the hybrid thin film. The m-SWCNTs/gold hybrid thin films with a 5 nm thick gold layer exhibited 300% improved conductivity compared to that of pristine gold thin films. Additionally, the regions with embedded m-SWCNTs showed significantly reduced noise source densities compared with pristine gold film regions. These results clearly show that embedded m-SWCNTs improve the conductivity and reduce electrical noises of metallic electrodes. Interestingly, we observed that the ρ and the Neff on both m-SWCNTs/gold hybrid and pristine gold regions exhibited a scaling behavior of ρ∝Neff0.5, implying the hopping charge conduction and noise characteristics of m-SWCNTs/gold hybrid films. Our works can be a useful guideline for the development of high performance electrodes based on CNTs.Graphical abstractImage 1
       
  • Measurement of thermal contact resistance between individual carbon fibers
           using a laser-flash Raman mapping method
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Qin-Yi Li, Koki Katakami, Tatsuya Ikuta, Masamichi Kohno, Xing Zhang, Koji Takahashi Thermal contact resistance (TCR) between individual carbon fibers (CFs) can dominate heat dissipation rates in CF-based composite materials. Here, we develop a totally non-contact “laser-flash Raman mapping” method to simultaneously measure the TCR at the CF-CF junction and their thermal conductivities. Laser power is used to heat the sample and the laser absorptivity is experimentally determined by a transient laser-flash Raman technique. The laser heating positions are changed along two connected CFs, and the change of temperature rise with varying positions is in-situ measured from the temperature dependent Raman band shifts. The high spatial resolution of the micro-Raman mapping allows direct observation of the abrupt jump of thermal resistance at the CF-CF junction, from which we extracted the TCR as well as the thermal conductivity. The laser absorptivity of the 11 μm-diameter CFs is measured to be 0.12 ± 0.03, the thermal conductivities of the individual CFs are around 200 W/mK, and the TCR of the CF-CF junction is (2.98 ± 0.92) × 105 K/W. This work provides indispensable knowledge for the design of CF-based composite for thermal management, and the novel non-contact measurement method can stimulate characterization and manipulation of contact/interface heat conduction between various micro- and nano-materials.Graphical abstractImage 1
       
  • A robust strategy for the general synthesis of hierarchical carbons
           constructed by nanosheets and their application in high performance
           supercapacitor in ionic liquid electrolyte
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Dewei Wang, Jiawang Nai, Hua Li, Lang Xu, Yatong Wang Porous nanocarbons are considered to be one of the key materials for electrochemical energy storage and conversion systems. In the present work, a straightforward one-step technique based on versatile magnesiothermic reduction combined with conventional KOH activation has been developed. We found that the magnesium (Mg) fulfilled multiple roles in the whole reaction and indispensable for achieving control over the organization of 2D nanobuilding blocks. Encouragingly, the same procedures can be successfully applied to a variety of carbon-rich chemicals as carbon sources to produce porous nanocarbons constructed by nanosheets. The intriguing structural features hold a great promise for electrochemical energy storage applications. As a typical example, the resultant HPCMC-1(synthesis from carboxymethylcellulose sodium) possesses unique interconnected carbon sheets network structures with a very large specific surface area and optimal bimodal microporous size distributions. The distinct structural features endow HPCMC-1 electrodes with excellent capacitive storage performance in ionic liquid electrolyte, which show large specific capacitance, good rate capability, long cycling performance and excellent synergetic energy-power outputting capabilities. Considering the general synthetic strategy together with the material sustainability, our work may open up another way for design and controllable fabrication nanocarbon architectures for applications in electrochemical energy storage fields with high performance.Graphical abstractImage 1
       
  • Effect of ball milling time on graphene nanosheets reinforced Al6063
           composite fabricated by pressure infiltration method
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Zhenhe Yu, Wenshu Yang, Chang Zhou, Ningbo Zhang, Zhenlong Chao, Hao liu, Youfang Cao, Yue Sun, Puzhen Shao, Gaohui Wu Evolution of graphene nanosheets (GNSs) during mechanical milling process was investigated to fabricate GNSs/Al nanocomposite by routes combined of pressure infiltration and hot extrusion. The structural integrity and dispersion homogeneity of GNSs together with the degree of interfacial reaction were systematically discussed. It was revealed that a moderate milling time existed for well dispersion and small quantities of Al4C3 (partial reaction bonding) via mechanical milling technique. A highest tensile strength of 276 MPa was obtained only with 0.3 wt% GNSs, which was 22.5% enhancement over the unreinforced Al matrix with the same preparation process and no decrease in elongation. Meanwhile, compared with reference Al, a great enhancement of electrical conductivity was achieved about 17.4%, which had not been reported previously. This study could provide new insights into the control factors of mechanical milling process for GNSs/Al composite and improve the interfacial bonding condition in situ during ball milling and subsequent densification processes to take full advantage of the extraordinary performance of graphene in metal matrix composites.Graphical abstractImage
       
  • Electrosprayed multiscale porous carbon microspheres as sulfur hosts for
           long-life lithium-sulfur batteries
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Xianying Qin, Junxiong Wu, Zheng-Long Xu, Woon Gie Chong, Jian-Qiu Huang, Gemeng Liang, Baohua Li, Feiyu Kang, Jang-Kyo Kim Highly conductive carbon microspheres (CMSs) with a hierarchical porous structure are prepared by electrospraying polystyrene/polyvinylpyrrolidine (PS/PVP) solution containing Ketjen carbon black (KB) nanoparticles. The branched KB particles serve as the structural skeleton to support CMSs while the hybrid polymer precursor forms multiscale pores upon pyrolysis. The CMSs possessing an extremely large pore volume of 2.08 cm3 g−1 and a large specific surface area of 756 m2 g−1 are melt-infiltrated with sulfur to form sulfur/CMS composite cathode for lithium-sulfur batteries. The cathode delivers a remarkable initial capacity of 1006 mAh g−1 at 1 C with high retention of 67.5% after 1000 cycles, and an initial capacity of 728 mAh g−1 at 2 C with high retention of 68.5% after 2000 cycles. The excellent electrochemical performance is attributed to the distinct functional and structural features of CMS framework: namely, microscale grain size, closely packed KB particles, large pore volume and hierarchical pore size, as well as superior conductive framework, which in turn suppress the shuttling of dissoluble polysulfides and boost the utilization of encapsulated sulfur. The above findings may offer insights into designing new carbon frameworks for other types of high performance rechargeable batteries.Graphical abstractImage 1
       
  • Tuning fluorine and oxygen distribution in graphite oxifluorides for
           enhanced performances in primary lithium battery
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): M. Mar, M. Dubois, K. Guérin, N. Batisse, B. Simon, P. Bernard Fluorine Graphite Intercalation Compounds are one of the most common cathode used in primary lithium batteries, mainly for their high delivering potential. Nevertheless, to increase their capacities, fluorine can be partially substituted by oxygen. Oxifluorides offer then versatility to design cathode materials delivering the upmost performances. Combining the choice of the precursor (either graphite oxide or sub-fluorinated graphite fluoride) and two-step synthesis processes, which include Hummers' oxidation and direct fluorination, allow the tuning of the fluorine and oxygen atoms distribution. According to the sequence, i.e. fluorination/oxidation or oxidation/fluorination, several oxifluorides were then prepared. On one hand, direct fluorination using F2 gas resulted in homogeneous fluorine dispersion when precursor was graphite oxide. On the other hand, Hummers’ oxidation was modulated according to the temperature parameter. COH, COC, COOH, CF, CF2 and CF3 were identified through multinuclear solid-state MAS-NMR. Covalence and environment, especially in-plane organization of those chemical groups, were assessed. When oxifluorides are then used as cathode in primary lithium battery, the better performances are obtained for 3 phases compounds where fluorinated part insured high potential whereas oxygenated part allowed durability to be reached; carbonaceous region providing conductivity. A maximum of about 2400 Wh/kg of energy density is attempted.Graphical abstractHigh performances of cathode materials for primary lithium battery have been obtained through bifunctionalization by fluorine and oxygen of graphite. Two steps synthesis: gas solid fluorination/Hummer's oxidation or oxidation/fluorination allow to get various functional groups and their repartition in graphite structure.Image 1
       
  • Multiphonon resonance Raman scattering in Landau-quantized graphene
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): Zi-Wu Wang, Zhi-Qing Li We theoretically investigate multiphonon resonance Raman scattering between the Landau levels in graphene on the polar substrate using the Huang-Rhys's model. We not only present the single and multiple surface optical (SO) phonons scattering, but also propose the combined multiphonon scattering, which is composed of the SO phonon and longitudinal acoustic phonon. We find that the combined multiphonon scattering has a blue-shift behavior with increasing the magnetic field, differing from these SO phonon resonance scattering occurred at specific magnetic field values. This behavior may be used to explain the changing shoulder of the Raman spectrum of optical phonon resonance scattering in experiments. The theoretical model could be expanded to analyze the fine structure of Raman spectrum in two-dimensional materials.Graphical abstractThe distribution of Landau levels in graphene in a strong magnetic field. The possible multiphonon resonance Raman processes are occurred between these Landau levels.Image 1
       
  • Investigation of the surface properties of different highly aligned
           N-MWCNT carpets
    • Abstract: Publication date: January 2019Source: Carbon, Volume 141Author(s): V. Eckert, E. Haubold, S. Oswald, S. Michel, C. Bellmann, P. Potapov, D. Wolf, S. Hampel, B. Büchner, M. Mertig, A. Leonhardt We investigated the physicochemical surface properties of different highly aligned nitrogen-doped multi-walled carbon nanotube (N-MWCNT) carpets, synthesized using toluene/pyrazine, toluene/benzylamine and acetonitrile via a sublimation-based chemical vapor deposition (SCVD) method at 760 °C. The surfaces of the N-MWCNT carpets synthesized using toluene/pyrazine and toluene/benzylamine were very hydrophobic. In contrast, we observed a complete wetting of the N-MWCNT carpets synthesized using acetonitrile. The difference in the wetting behavior of these N-MWCNT carpets is the main focus in this study and was not investigated before. Here, we show that not only the presence or concentration of nitrogen inside the carbon lattice, but especially it's kind of incorporation have an important influence on the surface polarity.Graphical abstractImage 1
       
  • Diamond film growth by HFCVD on Q-carbon seeded substrate
    • Abstract: Publication date: Available online 20 September 2018Source: CarbonAuthor(s): Ritesh Sachan, Anagh Bhaumik, Punam Pant, John Prater, Jagdish Narayan While hot-filament assisted chemical vapor deposition (HFCVD) is a well-established technique to synthesize diamond thin films using microdiamond seeds, the quality of grown diamond thin films is often compromised due to the presence of contaminants, i.e. graphitic entities and the eroded tungsten filament remnants, at the film-substrate interface. Here, we present a novel approach to form high-quality, contamination-free diamond thin films with HFCVD using Q-carbon precursor. The Q-carbon is a metastable phase which is formed by nanosecond laser melting of amorphous carbon and rapid quenching from the superundercooled state and consists of ∼75% sp3 and rest sp2 hybridized carbon. Using Q-carbon seeds in HFCVD, we demonstrate the growth of polycrystalline diamond film with a clean interface without any tungsten filament impurities. With large-area vibrational Raman mode analysis, we also observe a significant reduction in the presence of overall graphitic entities in the diamond film. With the realization of such a high-quality interface, we present a pathway to fabricate significantly improved diamond coatings and solid-state devices.Graphical abstractImage 1
       
  • Nitrogen ion implanted ultrananocrystalline diamond films: A better
           electrostatic charge storage medium
    • Abstract: Publication date: Available online 17 September 2018Source: CarbonAuthor(s): Kalpataru Panda, Jae-Eun Kim, Jeong Young Park Atomic force microscopy (AFM) is used to induce electrostatically charged areas on nitrogen-ion-implanted ultrananocrystalline diamond (UNCD) films by applying a bias voltage to the AFM tip during the tapping mode scan. For local and intentional electrostatic charging, both positive and negative charges can be stored on pristine as well as nitrogen-ion-implanted UNCD films, as detected by Kelvin probe force microscopy. Interestingly, the charge storage capacity of pristine UNCD increases with the N-ion implantation dose. The potential amplitude and spatial distribution of the trapped charges can be controlled by the bias and load applied to the tip. The enhanced charge storage properties with doping are attributed to the formation of impurities, various defects, and the induction of an enhanced graphitic sp2 phase because of the high N-ion implantation dose, where all act as trapping centres for extra charge. The formation of various defect states and conducting sp2 nanographitic phases facilitate enhanced charge storage in N-ion-implanted UNCD films. This study underscores the potential importance of doping-dependent charge storage and the role of defects and nanographitic phases as a strategy for enhancing the electrostatic charge storage capability of diamond-based charge storage devices.Graphical abstractImage 1
       
 
 
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