Effect of pH on electrocatalytic property of supported PtRu catalysts in proton exchange membrane fuel cell

Abstract

In this study, urea-assisted homogeneous deposition (HD) strategy is employed to synthesize Vulcan XC-72 (VC)-supported Pt-Ru (40 wt%) catalysts under various initial pH conditions. In situ generation of hydroxide ions through hydrolysis of urea at elevated temperature results in HD of Pt-Ru species on the VC support. In addition, it has been found that the initial pH value in the starting solution has significant influence on the Pt-Ru metal particle size and the catalytic activity of the supported Pt-Ru catalyst. Under most pH values investigated (i.e., higher than 5-6), the VC-supported Pt-Ru catalysts prepared by the HD approach have shown smaller metal particle size with better particle dispersion and demonstrated greatly improved anode catalyst performance over the one prepared by impregnation-NaBH4 reduction at pH 7-8 in proton exchange membrane fuel cell. The results presented in this work highlight that highly efficient Pt-based catalysts can be prepared by the HD strategy through the control of the initial pH value in the starting solution. (C) 2010 Elsevier B.V. All rights reserved.