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Methanol electro-oxidation on platinum modified tungsten carbides in direct methanol fuel cells:a DFT study

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posted on 2016-01-04, 11:56 authored by Tian Sheng, Xiao Lin, Zhao-Yang Chen, Peijun Hu, Shi-Gang Sun, You-Qun Chu, Chun-An Ma, Wen-Feng LinWen-Feng Lin
In exploration of low-cost electrocatalysts for direct methanol fuel cells (DMFCs), Pt modified tungsten carbide (WC) materials are found to be great potential candidates for decreasing Pt usage whilst exhibiting satisfactory reactivity. In this work, the mechanisms, onset potentials and activity for electrooxidation of methanol were studied on a series of Pt-modified WC catalysts where the bare W-terminated WC(0001) substrate was employed. In the surface energy calculations of a series of Pt-modified WC models, we found that the feasible structures are mono- and bi-layer Pt-modified WCs. The tri-layer Pt-modified WC model is not thermodynamically stable where the top layer Pt atoms tend to accumulate and form particles or clusters rather than being dispersed as a layer. We further calculated the mechanisms of methanol oxidation on the feasible models via methanol dehydrogenation to CO involving C-H and O-H bonds dissociating subsequently, and further CO oxidation with the C-O bond association. The onset potentials for the oxidation reactions over the Pt-modified WC catalysts were determined thermodynamically by water dissociation to surface OH∗ species. The activities of these Pt-modified WC catalysts were estimated from the calculated kinetic data. It has been found that the bi-layer Pt-modified WC catalysts may provide a good reactivity and an onset oxidation potential comparable to pure Pt and serve as promising electrocatalysts for DMFCs with a significant decrease in Pt usage.

Funding

Financial support from the EPSRC (EP/I013229/1), as part of the RCUK Energy Programme, the NSFC (21361140374 and 1321062) and International Science & Technology Cooperation Programme of China 2010DFB63680) is acknowledged.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Physical Chemistry Chemical Physics

Volume

17

Issue

38

Pages

25235 - 25243

Citation

SHENG, T. ...et al., 2015. Methanol electro-oxidation on platinum modified tungsten carbides in direct methanol fuel cells: a DFT study. Physical Chemistry Chemical Physics, 17 (38), pp. 25235-25243.

Publisher

© The Authors. Published by RSC.

Version

  • VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 3.0 Unported (CC BY 3.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by/3.0/

Publication date

2015

Notes

This is an Open Access Article. It is published by Royal Society of Chemistry under the Creative Commons Attribution 3.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/3.0/

ISSN

1463-9076

Language

  • en

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