Screening WS2-based single-atom catalysts for electrocatalytic nitrate reduction to ammonia

Electrocatalytic nitrate reduction to ammonia (eNRA) presents a promising approach for nitrate degradation and ammonia synthesis. The crucial factor in achieving efficient eNRA lies in the development of catalysts with high activity, selectivity, and stability. Herein, we utilized high-throughput first-principle computation to investigate the potential application of transition metal single atoms anchored on defective WS2 monolayer (WS2@TM) as electrocatalysts for eNRA. Sulfur defects naturally provide hosting sites for anchoring TM atoms on WS2 monolayer. Out of the 27 WS2@TM (3d to 5d period common TM's) catalysts considered, 16 are both thermodynamically stable and experimentally feasible. Among these 16 candidates, WS2@Fe and WS2@Co catalysts show promising potential, with limiting potentials of -0.40 and -0.27 V, respectively. Furthermore, the WS2@Fe and WS2@Co catalysts demonstrate high selectivity towards ammonia over hydrogen evolution reaction (HER) and by-products, indicating their potential as effective electrocatalysts for eNRA. This research comprehensively explores the discovery of novel eNRA catalysts and provides fundamental insights. It will also contribute to the development of efficient electrocatalysts for ammonia synthesis and encourage further experimental investigation in this field.