Antisite defect unleashes catalytic potential in high-entropy intermetallics for oxygen reduction reaction
Tao Chen, Xinkai Zhang, Hangchao Wang, Chonglin Yuan, Yuxuan Zuo, Chuan Gao, Wukun Xiao, Yue Yu, Junfei Cai, Tie Luo, Yan Xiang, Dingguo Xia
Abstract
Developing highly active, low-cost, and durable catalysts for efficient oxygen reduction reactions remain a challenge, hindering the commercial viability of proton exchange membrane fuel cells (PEMFCs). In this study, an ordered PtZnFeCoNiCr high-entropy intermetallic electrocatalyst with Pt antisite point defects (PD-PZFCNC-HEI) is synthesized. The electrocatalyst shows high mass activity of 4.12 A mgPt-1 toward the oxygen reduction reaction (ORR), which is 33 times that of the commercial Pt/C. PEMFC, assembled with PD-PZFCNC-HEI as the cathode (0.05 mgPt cm-2), exhibits a peak power density of 1.9 W cm-2 and a high mass activity of 3.0 A mgPt-1 at 0.9 V. Theoretical calculations combined with in situ X-ray absorption fine structure results reveal that defect engineering optimizes Pt’s electronic structure and activates non-noble metal site active centers, achieving exceptionally high ORR catalytic activity. This study provides guidance for the development of nanostructured ordered high-entropy intermetallic catalysts. The limited availability of efficient oxygen reduction reaction catalysts impedes the practical application of proton exchange membrane fuel cells. In this study, the catalytic activity of Pt-based high-entropy intermetallic is enhanced by regulating antisite defects.