Rational design of asymmetric atomic Ni-P1N3 active sites for promoting electrochemical CO2 reduction

The atomic-level interfacial regulation of single metal sites through heteroatom doping can significantly improve the characteristics of the catalyst and obtain surprising activity. Herein, nickel single-site catalysts (SSCs) with dual-coordinated phosphorus and nitrogen atoms were developed and confirmed (denoted as Ni-PxNy, x = 1, 2 and y = 3, 2). In CO2 reduction reaction (CO2RR), the CO current density on Ni-PxNy was significantly higher than that of Ni-N4 catalyst without phosphorus modification. Besides, Ni-P1N3 performed the highest CO Faradaic efficiency (FECO) of 85.0%–98.0% over a wide potential range of −0.65 to −0.95 V (vs. the reversible hydrogen electrode (RHE)). Experimental and theoretical results revealed that the asymmetric Ni-P1N3 site was beneficial to CO2 intermediate adsorption/desorption, thereby accelerating the reaction kinetics and boosting CO2RR activity. This work provides an effective method for preparing well-defined dual-coordinated SSCs to improve catalytic performance, targetting to CO2RR applications.