Self-functionalisation of axial ligand enhanced oxygen reduction activity in bimetal-atom catalyst

This study provides new insights into the self-functionalization effect of the axial ligand in (Fe–Co)–N–C bimetal atom catalysts in enhancing oxygen reduction reaction (ORR) activity. Using first-principles calculations and microkinetic modelling, we investigate the dynamic intermediate conversion mechanism on the catalyst active site during the ORR process. The theoretical results show that the Fe sites in (Fe–Co)–N–C are covered with *OH at U > UL. Interestingly, as *OH becomes part of the active site configuration, *OH–(Fe–Co)–N–C, the electronic properties are optimized, leading to improved predicted performance compared with pristine (Fe–Co)–N–C. This finding provides important theoretical insight into the underlying intermediate mechanism during the ORR process and offers guidance for further improving catalytic performance.