Effect of Preparation Conditions of Pt Alloys on Their Electronic, Structural, and Electrocatalytic Activities for Oxygen Reduction - XRD, XAS, and Electrochemical Studies

Abstract

The effect of different alloying conditions (alloying temperature, annealing period) on the electrocatalytic activities for the oxygen reduction reaction (ORR) by three carbon-supported Pt alloy electrocatalysts (Pt/Cr, Pt/Co, Pt/Ni) was investigated and correlated with electronic and structural parameters determined by in-situ XAS. The results indicate that all the Pt alloys show enhanced ORR activities relative to a Pt/C electrocatalyst. The observations indicate that the dependence of electrocatalytic activities and activation energy for Pt/Co and Pt/Ni alloys on the thermal history and the absence of such an effect in the Pt/Cr alloy could be related to the differences in the Pt 5d-orbital vacancies. 52 refs., 12 figs., 5 tabs.