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2 results on '"Doped carbons"'

1. Synthesis of (B-C-N) Nanomaterials by Arc Discharge Using Heterogeneous Anodes

Author

Virginie Serin, Flavien Valensi, Manitra Razafinimanana, Marc Monthioux, Raul Arenal, Sébastien Joulié, Djamel Eddine Gourari, LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Matériaux Multi-fonctionnels et Multi-échelles (CEMES-M3), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Arc Electrique et Procédés Plasmas Thermiques (LAPLACE-AEPPT), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Instituto de Nanociencia de Aragón [Saragoza, España] (INA), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3)

Subjects
Chemical compositions, Materials science, Electric arcs, Analytical chemistry, Carbon nanotubes, Optical spectroscopy, chemistry.chemical_element, Nanotechnology, High resolution transmission electron microscopy, 02 engineering and technology, Carbon nanotube, 01 natural sciences, 7. Clean energy, Electron spectroscopy, Nanomaterials, law.invention, Electric arc, Condensed Matter::Materials Science, Substitution rates, Single-walled carbon nanotubes (SWCN), law, 0103 physical sciences, Yarn, Electron energy levels, Electron scattering, Electron energy loss spectroscopy, 010306 general physics, Boron, High-resolution transmission electron microscopy, Electron temperature, Doped carbons, [PHYS]Physics [physics], Nanotubes, Graphene, Energy dissipation, Nitrogen plasma, Nanostructured materials, 021001 nanoscience & nanotechnology, Condensed Matter Physics, chemistry, Arc discharge, Plasmas, Optical emission spectroscopy, Optimal conditions, Core-level electrons, Plasma temperature, Electric discharges, 0210 nano-technology
Abstract

cited By 2; International audience; In spite of the current prevalence of the CVD-based processes, the electric arc remains an interesting process for the synthesis of carbon nanoforms, thanks to its versatility, robustness and easiness. It also allows performing in-situ substitution of carbon atoms by hetero-elements in the graphene lattice. Our work aims to establish a correlation between the plasma properties, type and chemical composition (and the substitution rate) of the obtained single-wall carbon nanotubes. The plasma was characterized by optical emission spectroscopy and the products were analyzed by high resolution transmission electron microscopy and core level Electron Energy-Loss Spectroscopy (EELS). Results show that a high boron content leads to a plasma temperature decrease and hinders the formation of nanotubes. This effect can be compensated by increasing the arc current and/or yttrium content. The optimal conditions for the synthesis of boron- and/or nitrogen-substituted nanotubes correspond to a high axial plasma temperature associated to a strong radial gradient. EELS analysis confirmed that the boron incorporates into the graphenic lattice.

Published
2016
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2. Simultaneous formation of nitrogen and sulfur-doped transition metal catalysts for oxygen reduction reaction through pyrolyzing carbon-supported copper phthalocyanine tetrasulfonic acid tetrasodium salt

Author

Xin Qing, Jingjing Shi, Mengyang Fan, Jiujun Zhang, Jinli Qiao, Zhongwei Chen, Zhengyu Bai, and Chengyu Ma

Subjects
Nitrogen, Inorganic chemistry, Energy Engineering and Power Technology, chemistry.chemical_element, Electrochemistry, Catalysis, Oxygen reduction reaction, Electron transfer, Transition metal catalysts, Transition metal, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Electrochemical measurements, Doped carbons, Copper phthalocyanine tetrasulfonic acid, Renewable Energy, Sustainability and the Environment, Chemistry, Electrolytic reduction, Active site, Loading, Copper phthalocyanine, Physical characterization, Copper, Sulfur, Carbon, Electron transitions, Catalyst activity, Pyrolysis, Transition metal compounds
Abstract

In this work, we report a spontaneous formation of copper (Cu-N-S/C) catalysts containing both nitrogen (N) and sulfur (S) elements using a one-step pyrolysis of carbon supported copper phthalocyanine tetrasulfonic acid tetrasodium salt (CuTSPc/C). The obtained catalysts exhibit high catalytic activities for oxygen reduction reaction (ORR) in alkaline media. Through electrochemical measurements and physical characterizations, several observations are reached as follows: (1) different pyrolysis temperatures can result in different catalyst structures and performances, and the optimum pyrolysis temperature is found to be 700 °C; (2) the electron transfer number of the ORR process catalyzed by the unpyrolyzed catalyst is about 2.5, after the pyrolysis, this number is increased to 3.5, indicating that the pyrolysis process can change the ORR pathway from a 2-electron transfer dominated process to a 4-electron transfer dominated one; (3) increasing catalyst loading from 40 μg cm-2 to 505 μg cm-2 can effectively improve the catalytic ORR activity, under which the percentage of H2O2 produced decreases sharply from 39.5% to 7.8%; and (4) the Cu ion can bond on pyridinic-N, graphite-N and C-Sn-C to form Cu-N-S/C catalyst active sites, which play the key role in the ORR activity. © 2014 Elsevier B.V. All rights reserved.

Published
2014

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