Nanostructure Engineering and Electronic Modulation of a PtNi Alloy Catalyst for Enhanced Oxygen Reduction Electrocatalysis in Zinc–Air Batteries
Xiangxiong Chen, Jiangnan Guo, Jinlong Liu, Ziyu Luo, Xinxin Zhang, Dong Qian, Dongxiao Sun‐Waterhouse, Geoffrey I. N. Waterhouse
Abstract
PtNi nanoalloys have demonstrated electrocatalysis superior to that of benchmark Pt/C catalysts for the oxygen reduction reaction (ORR), yet the underlying mechanisms remain underexplored. Herein, a PtNi/NC catalyst comprising PtNi nanoparticles (∼5.2 nm in size) dispersed on N-doped carbon frameworks was prepared using a simple pyrolysis strategy. Benefiting from the individual components and a hierarchical structure, the PtNi/NC catalyst exhibited outstanding ORR activity and stability ( E 1/2 = 0.82 V vs RHE and 8 mV negative shift after 20000 cycles), outperforming a commercial 20 wt % Pt/C catalyst ( E 1/2 = 0.81 V and 32 mV negative shift). A prototype zinc–air battery constructed using PtNi/NC as the air electrode catalyst achieved highly enhanced electrochemical performance, outperforming a battery constructed using Pt/C as the ORR catalyst. Density functional theory calculations revealed that the improved ORR activity of the PtNi nanoalloys originated from charge redistribution with a suitable metal d-band center to promote the formation of the ORR intermediates.