Positive Effect of Surface Doping with Au on the Stability of Pt-Based Electrocatalysts

Corrosion resistance of a transition-metal-rich PtCu 3 /C oxygen reduction reaction (ORR) catalyst as a representative of Pt alloy-based materials has been significantly improved by doping with small amounts of gold (<1 at. %). Transmission electron microscopy imaging shows near-surface segregation of both platinum and gold with the underlying core consisting predominantly of intermetallic PtCu 3 . The resulting PtAu skin catalyst shows improved resistance against Cu dissolution, as well as against carbon corrosion if compared to its PtCu 3 precursor. Also, it exhibits a much higher Pt and carbon stability than a widely used Pt/C standard. Most importantly, the Au-doped sample shows a substantial improvement in stability at the elevated temperature (60 °C) degradation test (10 000 cycles; 0.4–1.2 V RHE ) simulating a real PEM fuel cell environment.