Taming the challenges of activity and selectivity in catalysts for electrochemical N2 fixation via single metal atom supported on WS2

Abstract Developing the novel types of electrocatalysts with intrinsic stability, high activity and selectivity is a significant mission to advance the sustainable conversion of naturally abundant N2 to NH3, but it remains a long-standing challenge. Herein, through theoretical screening approach, focusing on addressing this challenge, we rationally designed a series of WS2 monolayer decorated by single transition metal (TM) atom as TM@WS2 candidates and systematically explored their potentials for catalyzing N2 reduction by building a full profile of stability, activity and selectivity. Our results unveil that, among 26 candidates, Cr@WS2, Tc@WS2 and Os@WS2 finally stand out as the most promising candidates, on which the adsorbed N2 molecule can be efficiently converted into NH3 through the distal mechanism with the limiting potentials of −0.37, −0.27 and −0.33 V, respectively, and impressively, the competing HER process can be pronouncedly inhibited. In particular, the activity trend is constructed by using *NNH adsorption energy and φ, and ICOHP reveals the origin of catalytic activity toward NRR. Our investigation not only contributes to the development of the highly efficient electrocatalysts, but also provides insightful views on the optimal design of WS2-based catalysts for advanced NH3 synthesis.