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      Platinum-modified covalent triazine frameworks hybridized with carbon nanoparticles as methanol-tolerant oxygen reduction electrocatalysts

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          Abstract

          Covalent triazine frameworks, which are crosslinked porous polymers with two-dimensional molecular structures, are promising materials for heterogeneous catalysts. However, the application of the frameworks as electrocatalysts has not been achieved to date because of their poor electrical conductivity. Here we report that platinum-modified covalent triazine frameworks hybridized with conductive carbon nanoparticles are successfully synthesized by introducing carbon nanoparticles during the polymerization process of covalent triazine frameworks. The resulting materials exhibit clear electrocatalytic activity for oxygen reduction reactions in acidic solutions. More interestingly, the platinum-modified covalent triazine frameworks show almost no activity for methanol oxidation, in contrast to commercial carbon-supported platinum. Thus, platinum-modified covalent triazine frameworks hybridized with carbon nanoparticles exhibit selective activity for oxygen reduction reactions even in the presence of high concentrations of methanol, which indicates potential utility as a cathode catalyst in direct methanol fuel cells.

          Abstract

          Covalent triazine frameworks are known catalysts for some catalytic reactions, but show no electrocatalytic activity. Here, the authors synthesize platinum modified covalent triazine frameworks hybridized with carbon nanoparticles, which are electro-active for oxygen reduction reactions.

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          Most cited references18

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          Identification of active gold nanoclusters on iron oxide supports for CO oxidation.

          Gold nanocrystals absorbed on metal oxides have exceptional properties in oxidation catalysis, including the oxidation of carbon monoxide at ambient temperatures, but the identification of the active catalytic gold species among the many present on real catalysts is challenging. We have used aberration-corrected scanning transmission electron microscopy to analyze several iron oxide-supported catalyst samples, ranging from those with little or no activity to others with high activities. High catalytic activity for carbon monoxide oxidation is correlated with the presence of bilayer clusters that are approximately 0.5 nanometer in diameter and contain only approximately 10 gold atoms. The activity of these bilayer clusters is consistent with that demonstrated previously with the use of model catalyst systems.
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            Platinum catalysts for the high-yield oxidation of methane to a methanol derivative

            Platinum catalysts are reported for the direct, low-temperature, oxidative conversion of methane to a methanol derivative at greater than 70 percent one-pass yield based on methane. The catalysts are platinum complexes derived from the bidiazine ligand family that are stable, active, and selective for the oxidation of a carbon-hydrogen bond of methane to produce methyl esters. Mechanistic studies show that platinum(II) is the most active oxidation state of platinum for reaction with methane, and are consistent with reaction proceeding through carbon-hydrogen bond activation of methane to generate a platinum-methyl intermediate that is oxidized to generate the methyl ester product.
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              From microporous regular frameworks to mesoporous materials with ultrahigh surface area: dynamic reorganization of porous polymer networks.

              High surface area organic materials featuring both micro- and mesopores were synthesized under ionothermal conditions via the formation of polyaryltriazine networks. While the polytrimerization of nitriles in zinc chloride at 400 degrees C produces microporous polymers, higher reaction temperatures induce the formation of additional spherical mesopores with a narrow dispersity. The nitrogen-rich carbonaceous polymer materials thus obtained present surface areas and porosities up to 3300 m(2) g(-1) and 2.4 cm(3) g(-1), respectively. The key point of this synthesis relies on the occurrence of several high temperature polymerization reactions, where irreversible carbonization reactions coupled with the reversible trimerization of nitriles allow the reorganization of the dynamic triazine network. The ZnCl2 molten salt fulfills the requirement of a high temperature solvent, but is also required as catalyst. Thus, this dynamic polymerization system provides not only highly micro- and mesoporous materials, but also allows controlling the pore structure in amorphous organic materials.
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                Author and article information

                Journal
                Nat Commun
                Nat Commun
                Nature Communications
                Nature Pub. Group
                2041-1723
                22 September 2014
                : 5
                : 5040
                Affiliations
                [1 ]Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656, Japan
                [2 ]Research Center for Advanced Science and Technology, The University of Tokyo, 1-5-3 Komaba, Meguro-ku , Tokyo 153-8904, Japan
                [3 ]Core Technologies Development Center, Eco Solutions Company, Panasonic Corporation, 1048 Kadoma , Kadoma-city, Osaka 571-8686, Japan
                Author notes
                Article
                ncomms6040
                10.1038/ncomms6040
                4199112
                25242214
                b264ed85-0c80-4fbf-9671-8c1649541f1e
                Copyright © 2014, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.

                This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

                History
                : 21 May 2014
                : 21 August 2014
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