Highly stable Pt3Ni nanowires tailored with trace Au for the oxygen reduction reaction

Abstract

One dimensional and bimetallic platinum nickel (PtNi) nanowires are a representative type of electrocatalyst with efficient oxygen reduction reaction (ORR) activity, while the catalytic stability is limited and still needs to be addressed. Herein, thin Pt₃Ni nanowires were successfully synthesized with superior ORR activity and stability compared with the commercial Pt/C catalyst, and notably, the durability of the catalyst can be further boosted by the in situ deposition of trace Au during the synthetic process without sacrificing the high ORR activity. The mass and specific activity of the optimized catalyst were 3.08 A mg_Pt⁻¹ and 5.74 mA cm⁻², respectively, which are approximately 14.7 and 16.9-fold that of a commercial JM Pt/C catalyst. Most importantly, the catalyst shows negligible performance degradation after 20 000 continuous potential cycles, and the structural stability of the catalyst was also confirmed by comprehensive measurements. The DFT data confirmed that decoration with Au atoms could effectively stabilize the Pt₃Ni structure and composition by reducing the defect sites of Pt₃Ni-skin and suppressing the dissolution of Ni atoms. This work provides a strategic approach for rational fabrication of high-performance ORR electrocatalysts with satisfactory durability.