Charge-asymmetry Fe₁Cu single-atom alloy catalyst for efficient oxygen reduction reaction

The development of high-efficient and low-cost oxygen reduction reaction (ORR) electrocatalysts is crucial for the practical applications of metal-air batteries. One promising way is to develop Fe single-atom catalysts. However, the single active center and inherent electronic structure of Fe single-atom catalysts lead to the undesirable adsorption of multiple ORR intermediates. Herein, a charge-asymmetry single-atom alloy (SAA) catalyst with Fe–Cu dual sites supported on nitrogen-doped carbon nanosheet (Fe₁Cu SAA/NC) was constructed. Various characterizations manifest the existence of electron interaction between Fe and Cu in Fe₁Cu SAA/NC, which facilitates the adsorption of ORR intermediate for fast kinetics. Consequently, the charge-asymmetry Fe₁Cu SAA/NC exhibits much faster ORR kinetics with a half-wave potential of 0.917 V vs. reversible hydrogen electrode (RHE), outperforming its counterparts in the references. Furthermore, Fe₁Cu SAA/NC still maintains a high half-wave potential with only a drop of 5 mV after 5000 cycles, indicating excellent stability. This work provides a new strategy to design highly active and non-noble metal ORR electrocatalysts, which hold great potential for various catalytic applications.