Preparation of porous PtAuCu@Pt core-shell catalyst for application to oxygen reduction

Designing a Pt-based catalyst with high oxygen reduction reaction (ORR) performance is very important for the improvement of the economic feasibility of polymer electrolyte fuel cells. Herein, we suggest a method to prepare a Pt-based core-shell catalyst with high ORR activity and durability by galvanic displacement between Cu on a thermally annealed sample of (Pt_xAu_y)₁Cu₅/C-HT and Pt ions. The resultant catalysts ((Pt_xAu_y)₁Cu₅@Pt/C) showed a porous core–shell structure with a Pt-enriched surface. The composition of (Pt_xAu_y)₁Cu₅/C-HT influenced the physical properties of the resultant (Pt_xAu_y)₁Cu₅@Pt/C catalysts. (Pt_xAu_y)₁Cu₅@Pt/C catalysts exhibited better ORR performance than a commercial Pt/C one and their performance varied with the composition. Among the catalysts examined, (Pt₁Au_0.1)₁Cu₅@Pt/C showed the best ORR activity. Specifically, it delivered a mass and specific activity of 0.660 mA/mg_PGM and 1506.2 mA/cm² _Pt at 0.9 V (vs. RHE), respectively. These are 2.7 and 4.2 times higher than corresponding values obtained for Pt/C. In an accelerated degradation test, addition of Au proved beneficial for the design of a highly durable catalyst. The effect of the Au content on the physical properties and ORR performance of catalysts was interpreted in detail.