EXAFS study Pt-Me/carbon supported catalytic systems
- Dr. Vladimir KRIVENTSOV
- Mr. E.P. YAKIMCHUK (Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia)
E.P. Yakimchuk1, V.V. Kriventsov1, B.N. Novgorodov1, D.P. Ivanov1, D.G. Aksenov1, D.A. Zyuzin1, N.S. Smirnova2, V.Z. Radkevich3, D.O. Antonov4, A.V. Chistyakov4, A.S. Fedotov4, S.A. Nikolaev5, M.V. Tsodikov4
1) Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia 2) Institute of Hydrocarbons Processing SB RAS, Omsk, Russia. 3) Institute of Physical Organic Chemistry NAS of Belarus, Minsk, Belarus. 4) Topchiev Institute of Petrochemical Synthesis, RAS, Moscow, Russia 5) Lomonosov Moscow State University, Department of Chemistry, Moscow, Russia
In recent years, few new types of carbon supported catalysts, such as activated carbon fibers, Busofit and CNF carbon nanofibers-based catalysts, inspire a growing interest. As rule, Busofit and CNF based catalysts have improved catalytic selectivity, activity and thermostability as compared to the traditional carbon supported catalysts using carbon-black or Sibunit as supports. This modification of catalytic properties is believed to result from higher accessibility of the deposited active component to the reactants and from strong interactions between the catalyst particles and the support surface. This work is devoted to the comparative structural study of few promising Pt, Pt-Me carbon-based catalytic systems using different carbon supports by the EXAFS methods: 1) Pt, Pt-Me Busofit-based catalysts for CO oxidation; 2) Pt, Pt-Me CNF-based cathode catalysts for PEMFC; 3) Pt, Pt-Me Sibunit-based catalysts for hydrocarbon conversion. Mesoporous granular carbon composite - Sibunit and carbon active fibers " Busofit (as woven activated carbon fabric modified with thermally stable acid groups) was used for prepaation of supported metal catalysts. Platinum in Pt- and PtMe-forms of Busofit was introduced from Pt(NH3)4Cl2 aqueous solution by means of impregnation and ion-exchange. A series of CNF with different arrangement of graphitic planes were synthesized by decomposition of methane and ethylene over transition metal catalysts. These structural types of CNF were used for preparation of the Pt, Pt-Me catalysts for PEMFC cathodes. Various synthetic techniques were studied, using H2PtCl6 and other Pt complexes as Pt precursors. All EXAFS spectra of the studied samples were recorded at Siberian Synchrotron and Terahertz Radiation Center (SSTRC, Novosibirsk). The local Pt and Me (Fe, Cu, Co) arrangements of all the samples studied were established and the phase compositions were determined. It was shown that there are some differences of the metal arrangements for the studied systems. All possible structural models were discussed. In addition, these samples were studied by the TEM, EDX and X-ray diffraction methods. The data of all methods are in a good agreement.
The work was done using the infrastructure of the Shared-Use Center “Siberian Synchrotron and Terahertz Radiation Center (SSTRC)” based on VEPP-3 of BINP SB RAS. This work was supported by RFBR (140301066, 163350248, 163350249, 163350250, 160301139), SB RAS comprehensive program II.2P (Project 0305-2015-0018).