Tungsten carbide as supports for Pt electrocatalysts with improved CO tolerance in methanol oxidation

One anti-CO-poisoning Pt-WC/C catalyst for methanol electro-oxidation is prepared in this work, through depositing platinum on tungsten carbide support using an intermittent microwave heating (IMH) method. The catalyst presents an improved methanol oxidation performance evidenced by a negative shift in onset potential, and increase of peak current density, compared with a commercial Pt/C one. CO stripping experiments indicate that the adsorbed CO is able to be oxidized and removed from the Pt-WC/C catalyst more easily, attesting the enhanced capability of anti-poisoning to CO-like species. Theoretical calculation further provides evidence that the surface electronic structure in Pt-WC/C and Pt/C catalysts is likely different. WC supports could lead to much stronger negative electronic property, which is beneficial for avoiding CO adsorption on the Pt-WC/C catalyst. In the mean time, the electron donating effect generated by WC supports also promotes the ability to oxidize the adsorbed CO-like species on catalysts. In good agreement with experimental results, the theoretical calculation proves the anti-CO-poisoning nature of the Pt-WC/C catalyst, and well explains the origin of the improvement in the electrochemical catalytic performance for effectively accelerating the oxidation of CO to CO2 in methanol oxidation. (C) 2011 Elsevier B.V. All rights reserved.