Core-shell structured tungsten-tungsten carbide as a Pt catalyst support and its activity for methanol electrooxidation
AuthorsObradović, Maja D.
Babić, Biljana M.
Radmilovic, V. R.
Krstajic, N. V.
Gojković, Snežana Lj.
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Tungsten carbide was synthesized by calcination of carbon cryogel containing tungsten in a form of metatungstate. Characterization by X-ray diffraction and transmission electron microscopy indicated core-shell structure of the particles with tungsten core and tungsten carbide shell, attached to graphitized carbon. Pt nanoparticles were deposited on this material and most of them were nucleated on tungsten carbide. Cyclic voltammetry of W-C support and Pt/W-C catalyst indicated hydrogen intercalation in surface hydrous tungsten oxide. Oxidation of COads on Pt/W-C commences earlier than on Pt/C for about 100 mV. The onset potentials of MOR on Pt/W-C and Pt/C are the same, but at more positive potentials Pt/W-C catalyst is more active. It was proposed that promotion of MOR is based on bifunctional mechanism that facilitates COads removal. Stability test was performed by potential cycling of Pt/W-C and Pt/C in the supporting electrolyte and in the presence of methanol. Pt surface area loss... observed in the supporting electrolyte of both catalysts after 250 cycles was about 20%. Decrease in the activity for methanol oxidation was 30% for Pt/W-C, but even 48% for Pt/C. The difference was explained by the presence of hydrous tungsten oxide on Pt in Pt/W-C catalyst, which reduces accumulation of poisoning COads. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:Methanol oxidation / CO oxidation / Platinum / Tungsten carbide / Electrocatalysis / Fuel cell
Source:International Journal of Hydrogen Energy, 2012, 37, 14, 10671-10679
- Reinforcing of Nanotechnology and Functional Materials Centre (EU-245916)
- Development, characterization and application nanostructured and composite electrocatalysts and interactive supports for fuel cells and water electrolysis (RS-172054)
- Nanotechnology and Functional Materials Center, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy [DE-AC02-05CH11231]