Asymmetric N, P-coordinated Co single-atom catalyst for efficient oxygen reduction reaction in Zn-air batteries

Simultaneously manipulating local atomic microenvironment and pore structure to design highly efficient single-atom catalysts for the oxygen reduction reaction (ORR) is a promising yet challenging approach. Herein, a two-pronged strategy is proposed to achieve asymmetric N and P coordinated atomically dispersed Co atoms on porous carbon nanosheets (denoted as d-CoN3P) for ORR in Zn-air batteries. Benefiting from the high intrinsic activity and densely exposed CoN3P active sites, the d-CoN3P catalyst demonstrates excellent ORR performance, with a half-wave potential of 0.895 V, an enhanced turnover frequency, and a large mass activity. Furthermore, the assembled Zn-air battery with a d-CoN3P cathode delivers a high specific capacity of 842 mA h g-1 along with long-term charge/discharge stability. Theoretical calculations further reveal that the CoN3P site adjusts the electron structure of the Co center, significantly reducing energy barriers and accelerating ORR kinetics. This work provides a new perspective on regulating the coordination microenvironment of single-atom catalysts for ORR.