Pre-lithiation depositing PtCu nanoparticles onto N-doped carbon as an efficient catalyst for oxygen reduction reaction

Abstract

In this study, a strategy for the preparation of nitrogen-doped carbon-loaded platinum-copper bimetallic catalysts (PtCu/NC, with a Pt loading of 3.49 wt%) based on the pre-lithiation deposition method was proposed to address the high cost and poor stability of ORR catalysts. PtCu alloy nanoparticles with core-shell structure (PtCu/NC-600, average particle size: 5.25 nm) were successfully constructed by optimizing the heat treatment temperature (400-800 ℃) and acid etching treatment, and the metal-support interaction was enhanced by using N-doped carbon-supports. Electrochemical tests showed that the PtCu/NC-600 catalyst exhibited excellent oxygen reduction reaction activity in acidic electrolyte, with a half-wave potential of 0.895 V, and mass-activity and specific-activity of 2.39 A mg_Pt^-1 and 1.88 mA cm_Pt^-2, which were significantly better than that of the commercial Pt/C catalyst (0.14 A mg_Pt^-1and 0.51 mA cm_Pt^-2). After accelerated durability testing, the half-wave potential of PtCu/NC-600 was only negatively shifted by 14 mV, with better stability than the comparison samples. Zinc-air batteries also show excellent performance. Theoretical calculations indicate that the alloying of Pt and Cu and the strong metal-support interaction between nitrogen-doped carbon and PtCu contribute to the activity and stability of the catalyst. This study provides a new idea for the development of low-cost and high-stability fuel cell catalysts.