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  Subjects -> CHEMISTRY (Total: 849 journals)
    - ANALYTICAL CHEMISTRY (50 journals)
    - CHEMISTRY (598 journals)
    - CRYSTALLOGRAPHY (22 journals)
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    - INORGANIC CHEMISTRY (42 journals)
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CHEMISTRY (598 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 32)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 227)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 14)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
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: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 13)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 158)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 208)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
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: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 283)
Biochemistry Insights     Open Access   (Followers: 5)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
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: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 108)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 93)
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: 2)
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: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 7)
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: 12)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 170)
Chemical Science     Open Access   (Followers: 21)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 55)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 144)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 226)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
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: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography Research International     Open Access   (Followers: 7)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
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: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 11)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 56)
Dalton Transactions     Full-text available via subscription   (Followers: 20)
Detection     Open Access   (Followers: 2)
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  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 9)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)

        1 2 3 | Last

Journal Cover Carbon
  [SJR: 2.109]   [H-I: 194]   [67 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0008-6223
   Published by Elsevier Homepage  [3042 journals]
  • How functional groups change the electronic structure of graphdiyne:
           Theory and experiment
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Niloofar Ketabi, Thomas M. Tolhurst, Brett Leedahl, Huibiao Liu, Yuliang Li, Alexander Moewes
      Graphdiyne's electrons have been verified to display near massless behavior, as was predicted by the Dirac cone-like shape of its band structure, and has thus resulted in an exceptionally promising semiconducting material. We present a study of three graphdiyne samples with different thicknesses grown using a cross coupling reaction. Their electronic structures were examined using synchrotron soft X-ray absorption and emission spectroscopy, together with complementary full-potential, all-electron density functional theory calculations. Excellent agreement between the measured and calculated spectra was achieved, indicating strong evidence that the correct structural model was found. We show the existence of oxygen molecules and hydroxyl functional groups, as well as pyridinic nitrogen sites in each graphdiyne sample studied. Our study shows that the defect type varies with sample thickness, which in turn strongly depends on the synthesis conditions. The band gaps of three graphdiyne samples were measured to be 0.6 eV, 0.8 eV, and 0.9 eV in agreement with our calculated values. We propose that controlling the thickness of graphdiyne films may provide a novel method for tuning their band gaps.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Novel tertiary dry solid lubricant on steel surfaces reduces significant
           friction and wear under high load conditions
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Abdullah A. Alazemi, Arthur D. Dysart, Steven J. Shaffer, Vilas G. Pol, Lars-Erik Stacke, Farshid Sadeghi
      A novel graphene-zinc oxide composite film is created and studied as a solid-state lubricant for friction and wear reduction under extreme load conditions. The liquid-free composite is made from a slurry of graphene, zinc oxide, and polyvinylidene difluoride spin-coated onto a stainless steel substrate. Enhanced tribological performance was measured under ambient conditions using a ball-on-disk tribometer with contact pressures up to 1.02 GPa and sliding distances up to 450 m. The graphene-rich lubricant demonstrates substantial friction and wear reduction (ca. 90%) compared to unlubricated sliding. The composite film is able to maintain its lubricating effects under extreme operating conditions including 15 N normal load and 450 m sliding distance. Following tribological testing, optical and spectroscopic analysis of the formed wear scars reveal a persistent protective film on the ball and disk surfaces. The excellent tribological performance of this graphene-rich composite is attributed to the adhesion effect from zinc oxide: zinc adheres graphene to the contact interface, maintaining improved tribological performance under high contact pressure. The durability and resilience of this adhesive coating suggest exceptional potential as a dry lubricant for high load-bearing applications.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Interfacial thermal resistance across graphene/Al2O3 and graphene/metal
           interfaces and post-annealing effects
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Daniel Villaroman, Xinjiang Wang, Weijing Dai, Lin Gan, Ruizhe Wu, Zhengtang Luo, Baoling Huang
      Chemical vapor deposited (CVD) graphene together with a superior gate dielectric such as Al2O3, are promising materials for next-generation high-speed field-effect transistors. Using the differential 3ω method, we have characterized the interfacial thermal resistance (ITR) across CVD graphene/Al2O3 and graphene/metal (Al, Ti, Au) interfaces from 100 to 330 K and investigated the effects of post-annealing on the interfacial thermal coupling for effective thermal management of those graphene-based devices. It was found that the ITR of graphene/Al2O3 is almost 5 times higher than the literature values for graphene/SiO2 interfaces while ITRs for graphene/metal, however, are much lower than that of graphene/Al2O3. It was also observed that ITR for graphene/Ti interface could be reduced by up to 40% through post-annealing. This reduction is attributed to the annealing-induced Ti-C covalent bonding on the interfaces. To explain the discrepancy between the experiments and conventional ITR models, we proposed a modified Diffuse Mismatch Model considering the interface coupling strength, which implies that the phonon transmission at the graphene interfaces is generally poor while annealing-induced bonding can improve the transmission. This work shows a scalable and inexpensive technique to improve graphene/metal thermal contacts.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Graphene and polytetrafluoroethylene synergistically improve the
           tribological properties and adhesion of nylon 66 coatings
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Muhammad T. Masood, Evie L. Papadopoulou, José A. Heredia-Guerrero, Ilker S. Bayer, Athanassia Athanassiou, Luca Ceseracciu
      In this work, we exploit the bidimensional structure and high stiffness of graphene to improve the tribological response of nylon-based composites. Graphene nanoplatelets, coupled with polytetrafluoroethylene microparticles, synergistically improve the friction coefficient and wear rate, as well as the adhesion to the substrate. The enhancement, as high as threefold for both friction and wear rate at the optimal graphene concentration (0.5% in weight), depends upon the formation of a continuous, robust transfer film with the steel rubbing counterpart, as shown by Raman measurements. The graphene-nylon coating also shows three-fold improved adhesion to the underlying substrate, attributed to the high surface energy of graphene.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Cellular carbon microstructures developed by using stereolithography
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Xu Chen, Guangbin Zhao, Yanlong Wu, Yajiang Huang, Yaxiong Liu, Jiankang He, Ling Wang, Qin Lian, Dichen Li
      Additive manufacturing has attracted much attention to generate structures containing ordered cells and customized shapes with various materials. A simple method was proposed to develop net-shape cellular carbon microstructures (CCMs) with controllable low shrinkage by using stereolithography. The polymer architectures, made of photosensitive resins, and sodium chloride were directly used as carbon precursors and granular support during carbonization, respectively. In addition, graphite powder was introduced into the granular support, which significantly enhances the mechanical property and electrical conductivity of the CCMs, and low graphite content has no significant effect on the volume shrinkage. The extremely high-porosity CCMs without distortion and breakage were obtained, showing controllable low volume shrinkage (44%–52%) with extremely low carbon yield (6%). The microstructure, mechanical property and electrical conductivity were measured and compared. It was found that the CCMs with graphite particles attaching on their surfaces show smooth surfaces with fewer defects, and possess great mechanical property (compressive stress and elastic modulus are 0.36 Mpa and 23.9 Mpa, respectively) and electrical conductivity (0.43 S/cm), which makes them promising materials for many potential applications.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Heat flow diversion in supported graphene nanomesh
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Ali Yousefzadi Nobakht, Seungha Shin, Kenneth D. Kihm, Drew C. Marable, Woomin Lee
      Redirection of energy carrier propagation by geometric confinement is studied through the analysis of in-plane and cross-plane thermal transport within various graphene nanomesh (GNM) configurations using molecular dynamics (MD) simulations. As the transport channel width decreases with an increase in porosity, the effect of redirection increases; thus, the in-plane thermal conductivity of large-porosity GNM is more dependent on hole arrangement. Since higher porosities weaken the GNM structure due to a larger population of broken bonds, carbon atoms within the graphene structures are more easily influenced by interactions with the substrate silicon (Si) block. Subsequently, increase in porosity leads to the decrease of interfacial thermal resistance. At higher porosities, lower interfacial resistance and in-plane thermal conductivity cause diversions (and redirections) in heat flow from the GNM to the underlying Si substrate. Our study suggests that this method of heat flow redirection can be applied as an effective means to control and manage heat transfer within numerous applications; extension to the improved conductivity calculation accuracy can also be achieved through the inclusion of this diversion analysis.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Activated carbon from the graphite with increased rate capability for the
           potassium ion battery
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Zhixin Tai, Qing Zhang, Yajie Liu, Huakun Liu, Shixue Dou
      Activated carbon has been synthesized by a high-temperature annealing route using graphite as carbon source and potassium hydroxide as the etching agent. Many nanosized carbon sheets formed on the particles could be of benefit for rapid intercalation/de-intercalation of potassium ions. Moreover, the d-spacing in the (100) crystal planes of the as-prepared active carbon is enlarged to 0.335 nm, even some formed carbon nanosheets can reach 0.358 nm, and the diffusion coefficient of K ion is also improved by 7 times as well. The as-prepared activated carbon electrode can deliver a high reversible capacity of 100 mAh g−1 after 100 cycles (at a high current density of 0.2 A g−1), and exhibits increased rate performance. The results demonstrate that the as-prepared active carbon is a promising anode material for the potassium ion battery, with high capacity, excellent rate performance, and great cycling stability.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Infinite spinning of several polyacetylene chains into long multiple
           helices
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Yunfang Li, Hongjin Fu, Weitao Lu, Shuqiong Xu, Xueqing Zhang
      This study demonstrates a designed multi-stranded helical motif that self-spun naturally by six to eight polyacetylene (PA) chains. The spiral of one end results in the helical behavior of the whole long polymer. We show that six PA chains with length of 1017.2 Å (1 nm) can self-spin continuously to form multiple helical structure. The basic strand-strand interaction, self-spun mechanism, and thermal stability during the natural helix-forming are particularly explained. The formed PA multiple helices are stable at room temperature. It is expected that these findings could stimulate enormous effects on the synthesis of helical polymers to further develop novel PA helix based functional materials and nanoscale devices.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Magnetic and fluorescent carbon nanotubes for dual modal imaging and
           photothermal and chemo-therapy of cancer cells in living mice
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Ming Zhang, Wentao Wang, Fan Wu, Ping Yuan, Cheng Chi, Ninglin Zhou
      Multi-walled carbon nanotubes (MWCNTs) have drawn increasing attention in biomedical fields because of their unique structures and properties, including good photothermal performance, large surface areas, strong near-infrared (NIR) absorbance, and size stability on the nanoscale. However, big challenge for this platform is to achieve fluorescence/magnetic resonance (MR) imaging and photothermal therapy (PTT) therapy in single nanotube. In this work, Multi-walled carbon nanotubes-magnetofluorescent carbon quantum dots/doxorubicin nanocomposites was prepared. The nanocomposite was then used as carriers for targeted drug transport in cancer therapy. These nanocomposites possess high heat-generating ability, pH and NIR responsive drug delivery, and heat-induced high drug release as well. Experiments in vitro and in vivo show that this platform can deliver anti-cancer drugs to targeted cells, releasing them intracellular upon NIR irradiation, and eliminate tumors effectively through chemo/photothermal synergistic therapeutic effect. Based on the findings of this work, further development of using other CNTs as highly efficient NIR agents can be achieved for vivo tumor imaging and chemo/photothermal synergistic therapeutic.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Etched nanoholes in graphitic surfaces for enhanced electrochemistry of
           basal plane
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Hongjie An, James Guo Sheng Moo, Beng Hau Tan, Sheng Liu, Martin Pumera, Claus-Dieter Ohl
      The understanding and tailoring of the electrochemistry of graphite is of significant industrial importance. We develop a method of etching pits into the basal planes of highly oriented pyrolytic graphite (HOPG) by electrolysis. The etching of HOPG was realized by performing electrochemical reactions at alternating potentials at room temperature, and the resulting membranes are characterized using atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectra, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectrscopy, and cyclic voltammetry. Etching only occurs when the electrolysis at negative bias is followed by a brief switch to a positive bias. The size of the etched pits can be tuned by varying the applied potential and reaction time, with deeper pits formed with increased redox cycles and reaction time. Cyclic voltammetry reveals that the electrochemical performance is enhanced greatly as etching progresses due to exposure of edge sites. For its ease of application, efficiency and low cost, our wet etching approach has great promise as a method to develop high active electrodes and nanoporous membranes at large scales for various industrial applications.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Manipulation of Dirac cones in intercalated epitaxial graphene
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Minsung Kim, Michael C. Tringides, Matthew T. Hershberger, Shen Chen, Myron Hupalo, Patricia A. Thiel, Cai-Zhuang Wang, Kai-Ming Ho
      Graphene is an intriguing material in view of its unique Dirac quasi-particles, and the manipulation of its electronic structure is important in material design and applications. Here, we theoretically investigate the electronic band structure of epitaxial graphene on SiC with intercalation of rare earth metal ions (e.g., Yb and Dy) using first-principles calculations. The intercalation can be used to control the coupling of the constituent components (buffer layer, graphene, and substrate), resulting in strong modification of the graphene band structure. It is demonstrated that the metal-intercalated epitaxial graphene has tunable band structures by controlling the energies of Dirac cones as well as the linear and quadratic band dispersion depending on the intercalation layer and density. Therefore, the metal intercalation is a viable method to manipulate the electronic band structure of the epitaxial graphene, which can enhance the functional utility and controllability of the material.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Structural analysis and oxygen reduction reaction activity in bamboo-like
           nitrogen-doped carbon nanotubes containing localized nitrogen in nodal
           regions
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Kaede Aoki, Ryosuke Senga, Yosuke Suga, Kenro Totani, Tei Maki, Hiroshi Itoh, Kiichiro Shinokura, Kazutomo Suenaga, Toshiyuki Watanabe
      Nitrogen-doped carbon nanotubes (N-CNTs) act as a metal-free catalyst for oxygen reduction reaction (ORR), but improving the ORR activity of N-CNTs remains challenging due to a lack of structural information. The N-CNTs with higher nitrogen concentration (an average surface nitrogen concentrations, 14.3 at.%) than the N-CNTs fabricated by conventional chemical vapor deposition method were synthesized using a dielectric barrier discharge in high pressure nitrogen and the spatial distribution of nitrogen in the N-CNTs was demonstrated by transmission electron microscopy in conjunction with electron energy loss spectroscopy. Nitrogen atoms were found to be concentrated at nodal regions in the bamboo-like structure, at concentrations above 23 at.%. At the point of the ORR, the highest onset potential was observed in the N-CNTs due to relatively highly incorporated pyridine-like nitrogen.
      Graphical abstract image

      PubDate: 2017-07-23T15:56:13Z
       
  • Electrically tunable large magnetoresistance in graphene/silicon Schottky
           junctions
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Xiaojuan Wang, Tao Wang, Dezheng Yang, Zhaolong Yang, Dong Li, Mingyuan Chen, Mingsu Si, Desheng Xue, Zengxing Zhang
      It should be a promising paradigm for graphene application in semiconductor industry by incorporating graphene into silicon to improve the behavior of silicon-based devices or develop high-performance devices with a new physical mechanism. Here we report on a large positive magnetoresistance (MR) over 80% at a magnetic field of 2.2 T and a temperature of 80 K in graphene/Si Schottky junctions by stacking chemical vapor deposition derived monolayer graphene on silicon. The produced MR is anisotropic and dependent on the angle between the direction of the magnetic field and the configuration plane, and can be modulated by the electrical bias across the configuration due to the built-in electric field. The MR effect should be ascribed to the charge carriers scattering and the released silicon magnetic moments in the graphene/Si interface that is suggested by first principles calculations. The study here should be helpful to understand the interface between the graphene and silicon, develop high-performance silicon based devices, complement the extraordinary properties of graphene and open one possible way to exploit their application for magneto-electronics.
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      PubDate: 2017-07-23T15:56:13Z
       
  • High temperature nanotribology of ultra-thin hydrogenated amorphous carbon
           coatings
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Youfeng Zhang, Kyriaki Polychronopoulou, Mohammad Humood, Andreas A. Polycarpou
      The present study utilizes a high-temperature nano-mechanical system to perform shallow tribology experiments on an ultra-thin (3 nm) hydrogenated amorphous (a-C:H) coating at elevated temperatures up to 300 °C. The nano-scratch experiments (single scratch) provide in-situ measurement of the friction coefficient and material deformation of the carbon film. The nano-wear experiments (repeated scratches over an area) investigate the extent of wear under multiple scratches. The two groups of experiments reveal the temperature dependence of the tribological behavior of the coating. Raman analysis is performed to compare the chemical structure of the carbon film before and after heating. The spectrum reveals both the hydrogen and sp3 content of the carbon film decrease after the high-temperature experiments, which contribute to deterioration of the wear resistance of the coating.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Evolution of implanted Fe ions in SiO2/Si wafer into uniformly sized
           catalyst particles for carbon nanotube forest growth
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Cheol-Hun Lee, Jaegeun Lee, Sunmog Yeo, Sung-Hyun Lee, Teawon Kim, Hyeon-Gu Cha, Youngmoo Eun, Hyun Jin Park, Seung Min Kim, Kun-Hong Lee
      We report the synthesis of carbon nanotube (CNT) forests with a narrow diameter distribution based on Fe ion implantation method. By annealing the Fe-implanted SiO2/Si wafer in an Ar atmosphere at 800 °C for 15 min, the Fe particles on the surface of SiO2 layer are successfully formed by the diffusion of Fe atoms from the SiO2 layer. Interestingly, the size distribution of Fe catalyst particles for Fe-implanted SiO2/Si wafers does not change with the prolonged annealing durations of up to 12 h. Using secondary ion mass spectroscopy and transmission electron microscopy (TEM), we confirmed that the implanted Fe atoms diffuse out of the SiO2 layer and form Fe particles on both the SiO2 surface and the interface between SiO2 and Si. The cross-sectional TEM images indicate that the Fe catalyst particles are anchored in the SiO2 layer, which limits the particles' mobility and results in an invariant catalyst size distribution for prolonged annealing durations. Therefore, we anticipate that implantation can be an efficient alternative catalyst preparation method for CNT forest growth which can solve various growth issues that are inherently caused by conventional physical vapor deposition method.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Encapsulation of two-dimensional materials inside carbon nanotubes:
           Towards an enhanced synthesis of single-layered metal halides
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Stefania Sandoval, Elzbieta Pach, Belén Ballesteros, Gerard Tobias
      The unique properties of two-dimensional (2D) nanomaterials make them highly attractive for a wide range of applications. As a consequence, several top-down and bottom up approaches are being explored to isolate or synthesize single-layers of 2D materials in a reliable manner. Here we report on the synthesis of individual layers of several 2D van der Waals solids, namely CeI3, CeCl3, TbCl3 and ZnI2 by template-assisted growth using carbon nanotubes as directing agents, thus proving the versatility of this approach. Once confined, the metal halides can adopt different structures including single-layered metal halide nanotubes, which formation is greatly enhanced by increasing the temperature of synthesis. This opens up a new strategy for the isolation of individual layers of a wide variety of metal halides, a family of 2D materials that has been barely explored.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Transformation from FeS/Fe3C nanoparticles encased S, N dual doped carbon
           nanotubes to nanosheets for enhanced oxygen reduction performance
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Changting Wei, Mengxia Shen, Kelong Ai, Lehui Lu
      Carbon nanotubes-supported non-precious metal nanoparticles emerge as promising catalyst candidate for fuel cell. Although it is well known that carbon nanotubes can influence the catalytic activity of transition metal nanoparticles, insights into whether the unrolling of carbon nanotubes can be exploited to enhance the oxygen reduction performance are lacking. Herein we demonstrate the transformation from FeS/Fe3C nanoparticles coupled S, N dual doped carbon nanotubes (FeS/Fe3C@S, N-C) to nanosheets can yield the improved oxygen reduction performance. Under a glucose protective strategy, the walls of FeS/Fe3C@S, N-C nanotubes were unrolled and extended, creating FeS/Fe3C nanoparticles coupled S, N dual doped carbon nanosheets (FeS/Fe3C@S, N-C g(50)) with larger surface area and higher doping level, which allowed for the exposure of sufficient accessible active sites. Consequently, FeS/Fe3C@S,N-C g(50) exhibited an onset potential of 0.938 V, together with low peroxide yield, good selectivity and durability. Our investigations showed that the carbon matrix with an opened structure and abundant accessible active sites is critical to the electrocatalysts. Furthermore, the synergetic effect of the S, N dual doped carbon nanosheets and FeS/Fe3C nanoparticles contributed to the enhanced oxygen reduction activity. We expect the presented structure–activity relationship can provide guidance for future design of advanced electrocatalysts.
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      PubDate: 2017-07-23T15:56:13Z
       
  • From mesoscale to nanoscale mechanics in single-wall carbon nanotubes
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Abraao C. Torres-Dias, Tiago F.T. Cerqueira, Wenwen Cui, Miguel A.L. Marques, Silvana Botti, Denis Machon, Markus A. Hartmann, Yiwei Sun, David J. Dunstan, Alfonso San-Miguel
      The analysis of the radial collapse of individualized and isolated single-wall carbon nanotubes under high pressure as function of their diameter, d, distinguishes their mesoscale and their nanoscale mechanics. The evolution with pressure of the Raman spectra for nine tube chiralities and the theoretical modelling reveal a deviation from the continuum mechanics prediction of a collapse pressure P C ∝ d − 3 . Nanotubes show a normalized collapse pressure P N = P C d 3 = 24 α D ( 1 − β 2 / d 2 ) both in experiment and in very different theoretical models. In this expression β = 0.44 ± 0.04 nm represents the smallest diameter for a stable freestanding single-wall carbon nanotube and D is the bending stiffness of graphene. From the experimental data D = 1.7 ± 0.2 eV . Deviations from the continuum mechanics predictions start to be of significance for diameters smaller than ∼ 1 nm . The associated reduction of their collapse pressure is attributed to the discretization of the elastic compliances around the circumference of the tubes.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Controllable synthesis of core-sheath structured aligned carbon
           nanotube/titanium dioxide hybrid fibers by atomic layer deposition
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Mingyang Li, Mei Zu, Jinshan Yu, Haifeng Cheng, Qingwen Li, Bing Li
      Carbon nanotube (CNT)-inorganic hybrids have been extensively investigated due to their potential to become the next-generation materials for applications in energy and environment. However, the random dispersion of CNTs and the low-quality inorganic phases may hinder their use in flexible and multi-functional devices. Herein, we synthesize the multi-functional aligned CNT/titanium dioxide (TiO2) hybrid fibers involving CNT-based continuous fibers coated by TiO2 through the atomic layer deposition (ALD). The aligned CNT/TiO2 hybrid fibers with various thicknesses of TiO2 layer can be simply obtained by changing the ALD cycles. Microscopic analysis of the surface morphologies and structures of the as-prepared hybrid fibers confirms the conformal oxide coating on the CNT fibers. Furthermore, the tensile strength of the hybrid fiber varies little after the deposition of TiO2 while its electrical conductivity decreases by 28.3% when the ALD cycle number is increased to 715 cycles. Due to its unique self-limiting characteristic, ALD has precise control in deposition at the atomic level and can facilitate the conformal and uniform coating of TiO2 on the CNT fibers while preserving the alignment of CNT bundles within the fiber, which may offer a promising solution for fabricating the novel multi-functional fibers.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Carbon nanotube/reduced graphene oxide hybrid for simultaneously enhancing
           the thermal conductivity and mechanical properties of styrene -butadiene
           rubber
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Shiqiang Song, Yong Zhang
      A novel hybrid of polymer functionalized-carbon nanotube @ reduced graphene oxide (PCNT@RGO) was prepared by reversible addition-fragmentation chain transfer polymerization, esterification reaction and reduction process. PCNT@RGO hybrid as a filler can effectively enhance the thermal conductivity and mechanical properties of styrene-butadiene rubber (SBR) vulcanizate. Remarkably, the tensile strength and stress at 200% extension of the SBR vulcanizate reached as high as 8.8 and 7.7 MPa at PCNT@RGO loading of 3 wt%, increasing by approaching 203% and 450% compared with neat SBR. Furthermore, the vulcanizate also exhibited high thermal conductivity (0.45 W/m K), which is 2.0-fold higher than that of SBR. The improvement in properties could be attributed to the synergetic effect of PCNT and RGO in PCNT@RGO hybrid, strong interfacial between PCNT@RGO and SBR matrix, the large constrained regions and continuous filler networks. Such good performances render the SBR/PCNR@RGO composite appealing for the use in various engineering practices.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Revealing impact of plasma condition on graphite nanostructures and
           effective charge doping of graphene
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Byeong-Joo Lee, Dong-Hoon Shin, Sangwook Lee, Goo-Hwan Jeong
      It is difficult to achieve effective doping without inducing structural damage in plasma-assisted processes. In this study, we demonstrate the effects of the plasma condition on the doping and defect formation in graphene. Direct-current ammonia plasma with parallel electrodes is used. We change the electrode configuration and adjust the plasma input power and treatment time to utilize various ion-bombardment energies and plasma doses. The up-cathode system with a powered upper electrode and ground lower anode is more suitable than the traditional down-cathode system for plasma doping. This configuration yields a low-energy ion process and thus suppresses high-energy ion-induced damages. The plasma condition of 0.45 W of power and exposure for 10 s is the most appropriate for doping. The doping level is estimated as 1.80 × 10 12 and 2.07 × 10 12 c m − 2 according to Raman analysis and electrical characterization, respectively. The structural evolution of graphene and the doping components are investigated via Raman spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. The results provide an effective doping condition for doping nanomaterials without plasma-induced damage.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Fabrication of hierarchical porous carbon microspheres using porous
           
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Liluo Shi, Yaxin Chen, Guanyu Chen, Yawen Wang, Xiaohong Chen, Huaihe Song
      Hierarchical porous carbon microspheres (HPCMs) have been fabricated by an impregnation-carbonization method using MgAl-layered double oxides (LDOs) microspheres as templates and sucrose as carbon source. The MgAl-LDOs microspheres templates are obtained via stacking and self-assembly of MgAl-layered double hydroxides particles in high-temperature calcination. The abundant hierarchical porous structure provides not only fast transport channels for ion diffusion but also facile access for non-aqueous electrolyte. Owing to the unique spherical structure, the prepared HPCMs possess the tap density of 0.825 g mL−1, the gravimetric capacities of 1140.5, 650.3, and 347.9 mA h g−1 and volumetric capacities of 940.9, 536.5 and 287.0 mA h cm−3 at the current densities of 0.05, 0.2, and 1 A g−1, respectively, when used as the anode for lithium ion batteries. This work presents a new strategy to prepare carbon microspheres, and the material with high specific capacity and good rate performance exhibits good prospect in lithium ion batteries.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Nanocatalytic conversion of CO2 into nanodiamonds
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Ali Reza Kamali
      Carbon dioxide was converted into Li2CO3 nano-single crystals with particle sizes below 30 nm using a reactive LiCl-Li2O molten salt method. The Li2CO3 nanocrystals were then in-situ encapsulated into carbon layers. Upon heating of the core-shell nanostructured carbon material, the nucleation of diamond crystallites within the nanostructure of carbon encapsulated Li2CO3 was demonstrated by high resolution transmission and scanning electron microscopy, X-ray diffraction and Raman spectrometry. The diamond crystallites could grow to micrometer-sized octahedral crystals by a further heating. These findings are of significance since they give insight into low-pressure nanocatalytic diamond nucleation and may also provide economic motivations towards the reduction of CO2 emissions.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Effect of surface modification of electrochemically oxidized carbon fibers
           by grafting hydroxyl and amine functionalized hyperbranched polyurethanes
           on interlaminar shear strength of epoxy composites
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Mohammad Andideh, Masoud Esfandeh
      Hyperbranched polyurethane (HBPU) structures functionalized with multiple OH groups (HBPU-OH) were synthesized and grafted onto the surface of carbon fibers (CFs) in order to improve interfacial properties between CFs and epoxy resin. Prior to grafting, CFs were electrochemically oxidized with nitric acid electrolyte solution to establish oxygen functional groups required for the grafting reaction. Then using a novel chemical technique, terminal multiple hydroxyl groups of HBPU grafted onto the surface of CFs (CFs-g-HBPU-OH) were converted to amino groups (CFs-g-HBPU-NH2). The functionalization composition, chemical structure changes and the polarity of the CFs surface were characterized in detail using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and dynamic contact angle analysis, respectively. Scanning electron microscopy (SEM) photographs and thermal gravimetric analysis (TGA) were employed to confirm the grafting reaction and to determine the grafting content. The results revealed that HBPU-NH2 was uniformly coated and grafted onto the surface of the fibers (CFs-g-HBPU-NH2), thus its potential use as the sizing agent for CFs tows is promising. Additionally, interlaminar shear strength (ILSS) was increased which was attributed to the improvement in fiber-matrix interface through enhanced chemical interactions and mechanical interlocking. This was in agreement with SEM observations from the fracture surface morphologies of the composites.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Adhesion energy of as-grown graphene on copper foil with a blister test
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Hao Xin, Russell Borduin, Wei Jiang, Kenneth M. Liechti, Wei Li
      Interfacial adhesion energy between as-grown graphene and its growth substrate reveals the nature of bonding, as well as provides insights for large-scale roll-to roll graphene transfer. In this study, a novel sample preparation scheme was developed and a unique quasi-static blister test was performed to measure the adhesion energy between as-grown graphene and its copper foil substrate. The copper foil was treated with acetic acid for 4 h, 24 h and 48 h prior to graphene growth. The corresponding adhesion energy was determined to be 0.74 ± 0.13 J/m2, 1.10 ± 0.16 J/m2, and 1.53 ± 0.11 J/m2, respectively. Longer exposures to acetic acid led to rougher copper foil surfaces, and thus higher adhesion energy. This trend is in contrast to that for transferred graphene, which has been found to have weaker adhesion to rougher substrates. The experimental results from this study suggest that the interaction between as-grown graphene and its seed layer was mainly due to van der Waals, instead of covalent or ionic bonds and that surface roughness of the growth substrate could be a significant factor in determining the as-grown graphene adhesion energy.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Metal organic frameworks templated sulfur-doped mesoporous carbons as
           anode materials for advanced sodium ion batteries
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 123
      Author(s): Xiaodong Shi, Yuxiang Chen, Yanqing Lai, Kai Zhang, Jie Li, Zhian Zhang
      In this paper, we focus on an innovative sulfur doping method with MOF-5 and inorganic sulfur powders as templated carbon precursor and sulfur source, in which sulfur powders were firstly encapsulated into the abundant pore structure of MOF-5 and then sulfur doping process could be realized through further pyrolysis treatment. Based on the results of material characterization, sulfur-doped mesoporous carbon (SPC) holds an amorphous structure with an enlarged interlayer distance of 0.386 nm and a mesoporous size distribution of 3–6 nm, while sulfur atoms existing in SPC (2.5 at.%) are mainly in the form of thiophene-type bonds (CSC and CS). Benefitting from the structural advantages, SPC electrode could display a long-term cycling stability with a reversible capacity of 173.7 mAh g−1 at 200 mA g−1 after 500 cycles and an outstanding rate capability of 104.9 and 90 mAh g−1 even the current raised up to 1.6 and 3.2 A g−1, respectively. The enhanced electrochemical performances could be mainly attributed to the introduction of S atoms into carbon structure, which can effectively enlarge the interlayer distance, improve the electronic conductivity and promote the insertion/extraction process of sodium storage.
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      PubDate: 2017-07-23T15:56:13Z
       
  • Roles of carbon nanotubes in novel energy storage devices
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Leimeng Sun, Xinghui Wang, Yanrong Wang, Qing Zhang
      Carbon nanotubes (CNTs), a typical one-dimensional carbon material, have been extensively studied for electrical and electronic applications for more than two decades. Owing to their unique morphology and outstanding electrochemical characteristics, CNTs are of promising potentials in energy storage applications. CNTs have been incorporated into the electrodes of batteries and supercapacitors as an active material and supporter. In recent years, the functions of CNTs in these energy storage devices have undergone a dramatic change. In this review, we summarize the roles of CNTs in novel energy storage devices, especially in Lithium-ion batteries and electrochemical supercapacitors. The new functions of CNTs in binder-free electrodes, micro-scaled current collectors and flexible and stretchable energy storage devices are also discussed.
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      PubDate: 2017-07-09T06:04:05Z
       
  • Engineering carbon materials with electricity
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Peter J.F. Harris
      The passage of an electric current, or the application of an electrostatic charge, can be used to modify the structure of carbon materials in a variety of ways. The simplest example of these involves the use of high current densities to produce electrical breakdown, as a result of Joule heating or electromigration. This has been used by a number of groups to create gaps in carbon materials in order to fabricate devices such as transistors. More complex structural transformations have been observed when electric fields are applied to carbon nanomaterials. These involve the formation of carbon structures made up of single-layer or bilayer graphene with highly irregular morphologies, displaying many unusual features, including nanotube–graphene junctions. Although the nature of these transformations is disputed, they may be partly a result of electrostatic charging rather than the passage of an electric current. It has also been demonstrated that electric fields can be used to induce exfoliation of graphite, both on the nano scale and macroscopically. This article is an attempt to provide an overview of the different ways in which carbon materials can be engineered using electricity. In addition to pure carbons, work on doped and filled nanotubes is covered, and the possibility of using electric fields in “graphene origami” is discussed.
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      PubDate: 2017-07-09T06:04:05Z
       
  • Carbon felt based-electrodes for energy and environmental applications: A
           review
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Thi Xuan Huong Le, Mikhael Bechelany, Marc Cretin
      Carbonaceous materials are abundantly used for electrochemical applications and especially for energy and environmental purposes. In this review, the carbon felt (CF) based-electrodes are discussed in a holistic manner. First of all, the study centers on the issues relevant to pristine CF materials such as manufacturing method and specific properties. The various methods and equations used to identify physical values of CF material are supplied. As main part of the review, the different modification methods for CF electrodes are described. The novel properties of fabricated materials are characterized by physical as well as electrochemical techniques. The strengths of each method are presented in the comparison with raw CF electrodes. The energy applications of CF based-electrodes are figured out in various fields such as vanadium redox flow batteries (VRFB), microbial fuel cells (MFCs), biofuel cells (BFCs), capacitors, solar cells and lithium ion batteries. For environmental applications, we focus our study on the wastewater treatment containing biorefractory pollutants by electro-Fenton (EF) process. The degradation result by EF technology using CF materials is impressive when most of toxic contaminants are mineralized to non-toxic compounds at the end of the electrolysis. To decrease the cost treatment and upgrade the treatment efficiency, the EF system has been improved by using modified electrodes or new catalyst sources. The CF materials are also investigated to apply in bio-fuel cell-Fenton in which electrons were produced from fuel cell (FC) towards zero-energy depollution. Finally, the sketches about EF pilot open new gates for application of CF materials in industrial areas.
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      PubDate: 2017-07-09T06:04:05Z
       
  • Comparison of black carbon concentration and particle mass concentration
           with elemental carbon concentration for multi-walled carbon nanotube
           emission assessment purpose
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Won-Geun Kim, Sang-Don Yong, Se-Jin Yook, Jun Ho Ji, Kyung-Hwan Kim, Gwi-Nam Bae, Eun-Kyo Chung, Jeong Ho Kim
      Elemental carbon (EC) can cause lung cancer or inflammation. Therefore, the objective of this study is to identify the possibility of real-time estimation of the EC concentration of multi-walled carbon nanotubes (MWCNTs) for workplace emission assessment. MWCNT aerosol particles were generated at a relatively constant rate over a period of 24 h, and the aerosolized MWCNTs were generally smaller than 1 μm. On-line measurement was performed by using an aethalometer and a scanning mobility particle sizer (SMPS) to determine black carbon (BC) concentration and particle mass concentration of the MWCNTs, respectively. Off-line analysis was conducted according to the National Institute for Occupational Safety and Health (NIOSH) method 5040 to obtain EC concentration of the MWCNTs. Then, correlations among the BC concentration, particle mass concentration, and EC concentration were investigated for the MWCNT particles. The particle number concentration converted from the SMPS measurement data and the BC concentration measured by the aethalometer were found to be in linear relation with the filter-sampling-based EC concentration, when the EC concentration of the MWCNTs was determined by the NIOSH method 5040. It is therefore anticipated that the use of the aethalometer and the SMPS can be of great help to the MWCNT emission assessment.
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      PubDate: 2017-07-09T06:04:05Z
       
  • Soft template-assisted method for synthesis of nitrogen and sulfur
           co-doped three-dimensional reduced graphene oxide as an efficient metal
           free catalyst for oxygen reduction reaction
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Yi Li, Juan Yang, Jipei Huang, Yazhou Zhou, Kai Xu, Nan Zhao, Xiaonong Cheng
      Developing earth-abundant materials to replace platinum (Pt)/Pt-based materials is an inevitable tendency for the progress of fuel cells due to the practical application limits. Recently, heteroatoms doped (N, S et al.) carbon materials, such as carbon nanotubes and graphene, have attracted great interests because of their amazing electrochemical activity towards oxygen reduction reaction (ORR). Herein, nitrogen and sulfur dual-doped three-dimensional reduced graphene oxide (NS-3DrGO) catalysts have been synthesized by a soft template-assisted approach followed by heat-pyrolysis treatment. Results indicate that with high specific surface area, sufficient porous structures, as well as the well-dispersed and doped atoms of N and S, the NS-3DrGO catalysts possess high onset/half-wave potentials together with large diffusing-limiting current density and present a four-electron transfer process in alkaline media. Specifically, at a relatively higher annealing temperature of 950 °C, the NS-3DrGO catalyst presents the optimal ORR activity compared with the others, which may be due to its highest amount (74.8 at. %) of the two active nitrogen species (pyridinic N and graphitic N) and the highest amount (79.8 at. %) of active thiophene-S together with the desirable specific surface (391.9 m2 g-1) area and multi-porous structure. Furthermore, the NS-3DrGO catalysts also exhibit superior methanol tolerance and favorable durability.
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      PubDate: 2017-07-09T06:04:05Z
       
  • Graphene oxide templated nitrogen-doped carbon nanosheets with superior
           rate capability for sodium ion batteries
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Zhigao Luo, Jiang Zhou, Xinxin Cao, Sainan Liu, Yangshen Cai, Lirong Wang, Anqiang Pan, Shuquan Liang
      Doping of N atoms into the carbonacous materials can generate extrinsic defects and more active sites, improve electrode wettability and also broaden the interlayer distance of carbon, hence promote Na storage capacity and high rate capability. Herein, we report the nitrogen-doped carbon nanosheets materials (PPyCs) obtained from pyrolysis of Polypyrrole coated graphene oxides. The pyrolysis temperature plays an important role on the electrochemical performance of PPyCs. With thermal treatment at 400, 600 and 800 °C, PPyCs have different content of N doping, and the doped N shows different existential forms. The PPyCs thermal treated at 600 °C (PPyC-600) exhibit a reversible capacity of 388.8 mA h g−1 at a current density of 100 mA g−1, and even at a high current density of 10 A g−1, high capacity of 198.6 mA h g−1 is maintained after 10,000 cycles, demonstrating outstanding cyclic stability, and high-rate capability. Furthermore, the assembled NVP/PPyC-600 full-cell demonstrates a high capacity of 122.2 mA h g−1 at a current density of 100 mA g−1 after 100 cycles, indicating the practical application of PPyCs nanosheets anode in sodium ion batteries.
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      PubDate: 2017-06-28T09:27:20Z
       
  • Electrical transport through atomic carbon chains: The role of contacts
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Ferdaous Ben Romdhane, Jean-Joseph Adjizian, Jean-Christophe Charlier, Florian Banhart
      Chains of carbon atoms in the sp 1 hybridization are the one-dimensional analog of graphene. The first experimental studies of electrical transport in atomic carbon chains have shown a much lower conductivity than the quantum conductance limit. Here we explain, experimentally and by ab-initio transport modeling, the limited conductivity by studying the influence of carbon contacts in different hybridization states on the electrical properties of carbon chains. In-situ measurements in an electron microscope allow the synthesis and electrical characterization of carbon chains. Current-voltage curves of carbon chains, spanning between carbon contacts with sp 2 -or sp 3 -hybridized contact atoms, are measured and calculated. Contact atoms in the sp 2 -hybridization allow up to two orders of magnitude higher current than through sp 3 contacts. Another important factor is the electron distribution in the chain which is determined by an even or odd number of atoms. On the other hand, it is shown that the overall length of the chain and strain have only minor influence on the conductivity. A current carrying capacity of up to 6.5 μA at an applied voltage of 1.5 V is measured.
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      PubDate: 2017-06-28T09:27:20Z
       
  • Ultrafast carrier transfer evidencing graphene electromagnetically
           enhanced ultrasensitive SERS in graphene/Ag-nanoparticles hybrid
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Yujin Wang, Hailong Chen, Mengtao Sun, Zehan Yao, Baogang Quan, Zhe Liu, Yuxiang Weng, Jimin Zhao, Changzhi Gu, Junjie Li
      Graphene-metal hybrid systems are highly promising as a very important building block in plasmonic structure for biosensing and catalyzing applications. However, the potential and mechanism of graphene in plasmon enhancement for such hybrids are not clear enough, although the corresponding enhancement of light-matter interaction has been reported. Here, we report an ultrafast optical spectroscopy investigation of a graphene/Ag-nanoparticles (NP) hybrid structure and evidence photo-carrier transfer from graphene to the Ag-NP. More importantly, we show that the graphene layer acts as an electron reservoir, and the electrons that transfer from it to the Ag-NP greatly enhance plasmon excitations therein, thereby generating giant local electromagnetic field enhancement in its hybrid. Further, we show that this graphene-derived local electromagnetic enhancement contributes greatly to ultrasensitive (10−13 M) surface-enhanced Raman scattering (SERS) in this hybrid. Our investigation reveals graphene's electromagnetic enhancement of SERS by uncovering an ultrafast carrier transfer mechanism in the graphene-plasmonic hybrid, and these results pave the way for the development of ultrasensitive plasmonic devices.
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      PubDate: 2017-06-28T09:27:20Z
       
  • Graphene-supported highly crosslinked organosulfur nanoparticles as
           cathode materials for high-rate, long-life lithium-sulfur battery
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Shuaibo Zeng, Ligui Li, Lihong Xie, Dengke Zhao, Ni Zhou, Nan Wang, Shaowei Chen
      Lithium-sulfur batteries represent one of the next-generation Li-ion batteries; yet rapid performance degradation is a major challenge. Herein, a highly crosslinked copolymer is synthesized through thermally activated polymerization of sulfur and trithiocyanuric acid onto the surface of reduced graphene oxide nanosheets. Of the thus-synthesized composites, the sample with a high sulfur content of 81.79 wt.% shows a remarkable rate performance of 1341 mAh g−1 at 0.1 C and 861 mAh g−1 at 1 C with an almost 100% coulombic efficiency. The composite electrode also effectively impedes the dissolution of polysulfides and their shuttle diffusion because of the abundant and robust chemical bonding between sulfur and trithiocyanuric acid and spatial confinement of polysulfides by the reduced graphene oxide sheets, which leads to 81.72% retention of the initial capacity even after 500 deep charge-discharge cycles at 1 C, corresponding to a decay rate of only 0.0404% per cycle. This performance is markedly better than those of comparative materials prepared in a similar fashion but at either higher or lower S loading, and among the highest in sulfur copolymer cathodes to date. The results provide an effective paradigm in the preparation and engineering of polymer cathode materials for high-performance lithium-sulfur batteries.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Direct synthesis of interconnected N, S-codoped porous exfoliated carbon
           nanosheets as advanced electrocatalysts for oxygen reduction reaction
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Ju-tao Jin, Xiao-chang Qiao, Fa-liang Cheng, Hong-bo Fan, Li-feng Cui
      The pursuit of porous carbonaceous materials with large specific surface area, well-defined pore structure and desirable dopants remain challenges for both energy storage and conversion. Here, we fabricate a novel interconnected N, S-codoped porous exfoliated carbon nanosheets (ECNs) with large specific area and pore volume through a one-step carbonization process by using glucose/melamine-sulphate-salt (GMSS) as precursor. By carefully examining the carbonization process of the precursor, we propose a phase separation mechanism for the formation of ECNs. The optimized sample, composed of interconnected thin graphite layers with N and S co-doping in the carbon lattice, exhibits outstanding ORR activity in terms of half-wave potential (0.83 V vs. RHE) and onset potential (0.97 V vs. RHE), together with 4-electron selectivity (H2O2 yield less than 8%), one of the best among all reported metal-free ORR catalysts.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Large magnetoresistance of amorphous carbon films
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Awais Siddique Saleemi, Rajan Singh, Wen Sun, Zhaochu Luo, Xiaozhong Zhang
      Magnetoresistance (MR) of pure amorphous carbon thin films deposited by pulsed laser deposition at various deposition temperatures was studied. Maximum MR of 46% was observed at 2 K under the magnetic field of 7 T for the sample deposited at temperature of 500 °C. No tendency of MR saturation was observed up to 7 T. The MR decreases rapidly with the increase in measurement temperature and vanishes after 40 K. The transport mechanism of all the samples follow Efros-Shklovskii variable range hopping model. The characteristics temperature decreasing from 2540 K to 1290 K and localization length increasing from 5.3 nm to 10.7 nm with increasing fraction of C(sp 2 ) from 72% to 84%. The lower disorder degree may results in higher MR.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Wettability of carbon nanotube fibers
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Luman Zhang, Jian Wang, Carlos A. Fuentes, Dongxing Zhang, Aart Willem Van Vuure, Jin Won Seo, David Seveno
      Carbon nanotube (CNT) fibers are interesting alternatives to carbon fibers as fibrous reinforcement. However, good interfacial adhesion between the fibers and the matrix is difficult to control. Wetting of the fiber reinforcement with the matrix strongly determines the interfacial strength. Therefore, accurate characterization of the wettability of CNT fibers is one of the most important cornerstones to improve the interfacial adhesion. In this work, dynamic contact angle measurements were conducted on individual CNT fibers by using a modified tensiometric method based on the Wilhelmy method combined with a synchronized optical observation. The CNT fiber-liquid interactions were monitored in-situ, and accurate measurements of the contact angles were achieved. Contact angles on CNTs were estimated through a modified Cassie-Baxter model on the basis of the experimental contact angle values of CNT fibers. Subsequently, the non-polar and polar surface energy components of the CNTs were obtained. Then, the wetting parameters (work of adhesion, spreading coefficient and wetting tension) were predicted by using the surface energy values of both the CNTs and a series of polymers (PP, MAPP, PET, PVDF, and PVA). The results indicate that PVA is in terms of wetting the most suitable matrix for the preparation of CNT fiber polymer composites.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Ductile behavior of fine-grained, carbon-bonded materials at elevated
           temperatures
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): J. Solarek, C. Himcinschi, Y. Klemm, C.G. Aneziris, H. Biermann
      Carbon-bonded materials are widely used in refractory applications because of their unique chemical, physical, and mechanical properties at high temperatures. The mechanisms of their high-temperature deformation are, however, unclear. The present study reveals new results from mechanical testing of both fine-grained, carbon-bonded alumina and graphite (ISEM 8) observed at temperatures of up to 1500 °C in an inert atmosphere. The results were achieved by means of microstructural investigations by scanning electron microscopy. For Al2O3-C, a pronounced maximum strength vs. testing temperature occurred at 1300–1400 °C, with a change from brittle to ductile behavior. In contrast, graphite showed an increase in strength until 1500 °C and no evidence of ductile deformation. A model based on the differences in the coefficients of thermal expansion of the components is presented to explain this phenomenon. In addition, Raman spectroscopy revealed the formation of graphitic structures due to testing at 1500 °C.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Monolayer polymerization of polyhedral oligomeric silsesquioxane on
           graphene oxide for highly efficient adsorption of β-lactoglobulin
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Yue Zhang, Zhiyong Guo, Lu Han, Yang Zhang, Xuwei Chen, Jianhua Wang
      We report the self-assembly of monolayer polyhedral oligomeric silsesquioxane (POSS) on graphene oxide (GO), where GO acts as a directing template along with the assembly of POSS into a three-dimensional porous framework structure, shortly termed as PPG. The PPG framework contains ultrathin nanopetals with a thickness of ca. 1.95 nm, giving rise to reduced restacking and high surface area. The PPG framework exhibits a high adsorption capacity of up to 1570.3 mg g−1 towards β-lactoglobulin, in addition to a favorable selectivity against other protein species with similar isoelectric points to that of β-lactoglobulin. This might be attributed to the specific hydrogen-bonding donor-acceptor interaction between the calyx structure of β-lactoglobulin and the PPG framework. Satisfactory separation performance of PPG is confirmed by the selective discrimination and isolation of β-lactoglobulin from complex biological sample matrixes, e.g., milk whey. This observation provides a promising approach for the construction of monolayer polymer-modified three-dimensional graphene oxide composites with specific biological application potentials.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Influence of carbonaceous materials on electronic conduction in
           electrode-slurry
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Mitsuhiro Takeno, Tomokazu Fukutsuka, Kohei Miyazaki, Takeshi Abe
      Carbonaceous materials have been used as conductive materials for the composite electrodes in lithium-ion batteries (LIBs). Since an increase in the amount of conductive material implies a decrease in the capacity of the LIB, the amount of conductive material used should be kept to a minimum. Carbonaceous materials as conductive materials have various morphology and crystallinity, therefore, the fundamental study of carbonaceous materials as conductive materials is important. In this study, the electronic conductivity of electrode-slurries and composite electrodes prepared using different carbonaceous materials (acetylene black (AB), fine graphite, and vapor grown carbon fiber (VGCF)) as the conductive material was investigated, and the effect of the different carbonaceous materials on the electron conduction network was discussed. In the electrode-slurry, AB and VGCF formed electron conduction paths and displayed high electronic conductivity. The electrode-slurry of AB displayed solid-like behavior, whereas the electrode-slurries of VGCF and graphite displayed fluid-like behavior. This difference influenced the electronic conductivity of the composite electrode.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Targeted removal of copper foil surface impurities for improved synthesis
           of CVD graphene
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Adrian T. Murdock, Christian D. van Engers, Jude Britton, Vitaliy Babenko, Seyyed Shayan Meysami, Hugh Bishop, Alison Crossley, Antal A. Koos, Nicole Grobert
      Commercially available Cu foils are leading candidates as substrates employed for the generation of large-area graphene using chemical vapour deposition (CVD) techniques. However, the growth of high-quality graphene on Cu foils is often hindered by contamination particles, which will also be detrimental for many potential applications of graphene. Here we investigate the influence of typical substrate impurities on the formation of CVD graphene using as-received Cu foils of various purities from different suppliers and the same cleaned by popular methods. Analytical characterisation of the Cu foils revealed that contamination particles consist of calcium, aluminium, and silicon oxides. We show that contamination particles are present on foils with purities ranging between 99.8% and 99.9999% and that these particles influence the nucleation density, growth rate, and growth features of graphene domains. Based on our findings we propose new industrially applicable targeted cleaning procedures of immersion in purposely-selected HCl and KOH solutions to chemically dissolve the aforementioned impurities, bringing about improved growth of graphene.
      Graphical abstract image

      PubDate: 2017-06-28T09:27:20Z
       
  • Catalytic growth of diamond-like carbon on Fe3C-containing carburized
           layer through a single-step plasma-assisted carburizing process
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Yang Yang, M.F. Yan, Y.X. Zhang, D.Y. Li, C.S. Zhang, Y.D. Zhu, Y.X. Wang
      This article reports a study on catalytic growth of diamond-like carbon (DLC) on the Fe3C-containing carburized surface layer of M50NiL steel through a single-step plasma-assisted carburizing process. The catalytic effect of Fe3C on DLC growth was investigated by means of X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mechanical and tribological tests demonstrate that the DLC growth endows the treated specimens with higher hardness, lower coefficient of friction and increased wear resistance than traditional carburization layer. First-principles calculations were conducted to verify the experimental observations and elucidate the mechanism for the catalytic growth of DLC on Fe3C surface. This study demonstrates that DLC can simultaneously form during carburization of steel under suitable processing conditions, resulting in a combination of DLC and carburized layers through a single-step process with help of the catalytic effect of Fe3C. This finding shows a promising approach to maximize the benefits of carburization treatment, and provides new clues for facilitating DLC production and improving traditional surface treatments for steels.
      Graphical abstract image

      PubDate: 2017-06-21T11:31:59Z
       
  • Palladium supported on reduced graphene oxide as a high-performance
           catalyst for the dehydrogenation of dodecahydro-N-ethylcarbazole
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Bin Wang, Ting Yan, Tieyan Chang, Jinjia Wei, Qiang Zhou, Sen Yang, Tao Fang
      Liquid organic hydrogen carrier technology has been considered the most promising scheme of alternative to liquid fossil fuels. However, incomplete dehydrogenation has been a bottleneck in the development, as the dehydrogenation catalysts do not have satisfactory catalytic properties. Here we report on a catalyst of Pd supported on reduced graphene oxide (rGO) prepared by ethylene glycol with excellent catalytic performance for the dehydrogenation of dodecahydro-N-ethylcarbazole (12H-NECZ). The Pd/rGO-EG catalyst exhibits a dramatically enhanced specific activity (up to 14.4 times) and uses half the amount of noble metals in contrast to the state-of-the-art commercial Pd/Al2O3 dehydrogenation catalyst. At 433, 443 and 453 K, amounts of dehydrogenation of 5.27, 5.49 and 5.78 wt%, respectively, were achieved using a 2.5 wt% Pd/rGO-EG catalyst. The dehydrogenation performance of Pd/rGO reduced by different reducing agents was irregular. The catalyst characterization of Pd/rGO-EG shows that Pd is uniformly distributed on the monolayer rGO, mainly in the form of single crystal, with the highest activity Pd (111) surface. A more accurate kinetic calculation was performed to obtain the rate constant of each elementary reaction of the dehydrogenation reaction.
      Graphical abstract image

      PubDate: 2017-06-21T11:31:59Z
       
  • Boron carbonitride coatings synthesized by LPCVD, structure and properties
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): G. Puyoo, F. Teyssandier, R. Pailler, C. Labrugère, G. Chollon
      Thin films of carbon-rich boron carbonitride (h-B-C-N) were prepared by low pressure chemical vapor deposition from C2H2, BCl3, NH3 and H2 mixtures. After an overall investigation of the deposition kinetics and the composition of the solid, four deposition conditions were selected to study in details the structure, the oxidation behavior and the mechanical properties of the deposits. The influence of the gas phase composition on the atomic concentration and the microstructure of the material was first investigated. Carbon rich coatings are turbostratic and highly textured, whereas boron nitride-rich coatings are more disordered and less anisotropic. We examined their oxidation behavior in the range 450 °C–700 °C, under both dry and ambient air. The oxidation resistance of the h-B-C-N coatings strongly depends on the deposition temperature and is improved by heat treatments. It is significantly better than that of pyrolytic carbon in dry air but worse in wet air, because of the reactivity of B2O3 with H2O. The room temperature stress/strain behavior of unidirectional SiC/SiC composites with h-B-C-N interphases is elastic and damageable as in the case of reference composites having a pyrolytic carbon interphase.
      Graphical abstract image

      PubDate: 2017-06-21T11:31:59Z
       
  • Fractal carbon nanotube fibers with mesoporous crystalline structure
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): H. Yue, V. Reguero, E. Senokos, A. Monreal-Bernal, B. Mas, J.P. Fernández-Blázquez, R. Marcilla, J.J. Vilatela
      Macroscopic fibres of carbon nanotubes are hierarchical structures combining long building blocks preferentially oriented along the fibre axis and a large porosity arising from the imperfect packing of bundles. Synchrotron small-angle X-ray scattering (SAXS) measurements show that such structure is a surface fractal with fractal dimension (D s ) of 2.5 for MWCNT fibres and 2.8 for SWCNT fibres. N2 adsorption measurements give similar values of 2.54 and 2.50, respectively. The fractal dimension and deviation from Porod's law are related to density fluctuations associated with the wide distribution of separations between CNTs. These fluctuations are also evident as diffuse wide-angle X-ray scattering (WAXS) from CNTs at distances above turbostratic separation. The structure of CNT fibres produced at different draw ratios is compared in terms of degree of orientation and characteristic lengths parallel and perpendicular to the fibre. Drawing not only increases alignment but also the fraction of graphitic planes forming coherent domains capable of taking part in stress transfer by shear; thus increasing both tensile modulus and strength. The invariant-normalized intensity of the (002) equatorial reflection thus takes the form of a degree of crystallinity closely related to tensile properties.
      Graphical abstract image

      PubDate: 2017-06-21T11:31:59Z
       
  • Interwoven N and P dual-doped hollow carbon fibers/graphitic carbon
           
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Huachao Tao, Lingyun Xiong, Shaolin Du, Yaqiong Zhang, Xuelin Yang, Lulu Zhang
      Flexible and thin energy storage devices have attracted enormous attentions. An easy and large-scale method has been employed to fabricate flexible and interwoven N, P dual-doped carbon fibers/graphitic carbon nitride (huCP/g-C3N4) using filter paper as a precursor. The huCP/g-C3N4 composite as self-supporting anode for lithium ion batteries exhibits high reversible capacities of 1030 mAh g−1 after 1000 cycles at 1 A g−1 and 360 mAh g−1 after 4000 cycles at 10 A g−1 along with excellent rate performance (133 mAh g−1 at 30 A g−1). For sodium ion batteries, huCP/g-C3N4 as anode delivers high reversible capacities of 345 mAh g−1 after 380 cycles at 0.1 A g−1 and 110 mAh g−1 after 4000 cycles at 1 A g−1. This excellent electrochemical performance can be attributed to the high contents of doped N and P in huCP/g-C3N4 and graphitic carbon nitride network, which not only create more defects and active sites but also expand the layer planes and provide interconnected conductive network.
      Graphical abstract image

      PubDate: 2017-06-21T11:31:59Z
       
  • N and P co-functionalized three-dimensional porous carbon networks as
           efficient metal-free electrocatalysts for oxygen reduction reaction
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Hao Jiang, Yanqiu Wang, Jiayu Hao, Yisi Liu, Wenzhang Li, Jie Li
      Developing low-cost and high-performance metal-free oxygen reduction reaction (ORR) catalysts for fuel cells is highly desirable but still full of challenges. In this study, nitrogen and phosphorus co-functionalized three-dimensional (3D) porous carbon networks (NPCN) have been prepared by pyrolysis the zero-dimensional carbon quantum dots (CQDs) and a supermolecular gel of self-assembled melamine and amino trimethylene phosphonic acid (ATMP). The resultant NPCN catalysts possess unique 3D networks-like porous architecture, large specific surface area (743 m2 g−1) and abundant edge defects. As a catalyst for ORR, the optimized NPCN-900 (pyrolyzed at 900 °C) displays positive onset potential at 0.92 V and 0.74 V (vs. RHE) in alkaline and acidic media respectively, which are roughly close to those of Pt/C (0.93 V and 0.80 V). Additionally, the NPCN-900 exhibits longer-term stability and strong endurance to methanol over a wide pH range of aqueous media, which is much superior to that of Pt/C. Considering the outstanding activity of NPCN-900, it can be worked as a prospective metal-free catalyst to substitute commercial Pt/C for ORR in fuel cells.
      Graphical abstract image

      PubDate: 2017-06-21T11:31:59Z
       
  • Graphene paper for exceptional EMI shielding performance using large-sized
           graphene oxide sheets and doping strategy
    • Abstract: Publication date: October 2017
      Source:Carbon, Volume 122
      Author(s): Yan-Jun Wan, Peng-Li Zhu, Shu-Hui Yu, Rong Sun, Ching-Ping Wong, Wei-Hsin Liao
      Large-sized graphene sheets (LG) and doping strategy were employed to fabricate lightweight and flexible graphene paper with exceptional electromagnetic interference (EMI) shielding performance. Compared with the smaller sized ones, LG with fewer defects and more conjugated carbon domain size as well as better alignment result in higher electrical conductivity and strength of graphene paper. The iodine doping further improves the carrier density of LG by formation of triiodide ( I 3 − ) and pentaiodide ( I 5 − ) through charge transfer process without deteriorating the mechanical property, thus leading to superior EMI shielding effectiveness (SE). The EMI SE of iodine doped LG film with thickness of 12.5 μm is up to ∼52.2 dB at 8.2 GHz, which is much higher than that of undoped LG with the same thickness (∼47.0 dB). More important, the improvements in EMI SE is contributed to the SE absorption, while the SE reflection is almost unchanged. The mechanisms of improved EMI shielding performance as well as mechanical property were investigated and discussed. The present study provides a facile way to fully develop graphene in lightweight and flexible EMI shielding materials and devices.
      Graphical abstract image

      PubDate: 2017-06-21T11:31:59Z
       
 
 
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