Surface Composition Engineering of PtCu Nanoframe Catalyst to Improve Electrochemical Stability for Oxygen Reduction Reaction

Abstract

Alloy nanoframes have drawn wide attention in the field of electrocatalysis because of their high specific surface area, molecule accessible 3D pore structure, and excellent catalytic performance. However, due to abundant edges and corners, nanoframes are easy to collapse during the catalytic process, especially for oxygen reduction reaction. Herein, PtCu nanoframes are prepared through wet-chemical method and modified with Mo (Mo-PtCu NF) on the surface to improve the structural stability. Fully open nanoframe catalyst (A-Mo-PtCu NF/C) is finally obtained by selective etching excess Cu in Mo-PtCu NFs. Due to the synergistic effect of Cu and Mo, the electronic structure of Pt in A-Mo-PtCu NF/C is optimized to weaken the oxygen affinity. Meanwhile, the highly open structure of A-Mo-PtCu NF/C provides a large electrochemically active area. Therefore, the as-prepared nanoframe catalysts show enhancements in both mass activity and specific activity compared to the commercial Pt/C catalyst. Moreover, Mo-doping also stabilizes the structure and composition of the nanoframes, enhancing the stability for oxygen reduction reaction. Our research provides an effective strategy to improve the stability of highly active alloy nanoframes.