Synthesis of an active and stable Pt-shell-Pd-core/C catalyst for the electro-oxidation of methanol

Abstract

A Pt-shell-Pd-core/C catalyst is prepared via electroless deposition and galvanic displacement. The catalyst is active toward the electro-oxidation of methanol and is more stable against COad-poisoning than a commercial Pt/C catalyst. The stable activity of Pt-shell-Pd-core/C is ascribed to the tuned electronic property of the Pt over-layer in the Pt-shell-Pd-core/C, which leads to weak binding with COad and increases the kinetics of OHad formation. The weakened binding property of the surface Pt with COad and the facile oxidation of COad by OHad were confirmed by a spectroscopic analysis and in a COad-stripping experiment, respectively. The electro-oxidation of COad by Had is the rate-determining step of methanol oxidation. Therefore, the accelerated formation of OHad contributes to the overall oxidation reaction, preventing COad-poisoning. In addition, Pt-shell-Pd-core/C maintains its activity longer than Pt/C does during a prolonged cycle experiment. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.