Axial Coordination Regulating Single Atoms for Enhanced CO₂ Electroreduction

With the merits of high atomic utilization and well‐defined configuration, metal−nitrogen−carbon (M−N−C) single‐atomic catalysts (SACs), show great capability in selective reduction of CO 2 into CO and formate. However, the metal center with the planar configuration of M−N 4 has a highly symmetric structure, which is not conductive to charge transfer, thus limiting the intrinsic activity of SACs. Introduction of axially coordinated atoms with M−N 4 center can break the symmetry and optimize the intermediate adsorption for accelerating CO 2 reduction. Here, we briefly discuss the CO 2 RR pathway on single atoms and introduce the emerging synthetic methods for SACs with axial ligands. Then we review the axial coordination effect on CO 2 RR behavior. This review will be helpful for understanding the working mechanism of axially coordinated single atoms for enhancing CO 2 RR performance and thereby designing ideal coordination ligand in the axial direction.