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

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.