Single-atom W anchored Janus transition metal dichalcogenides as a promising catalyst for the ammonia synthesis

Electrochemical nitrogen reduction reaction (NRR) has emerged as an eco-friendly and economical tactic for ammonia synthesis recently. However, for most NRR catalysts, high overpotential and low Faraday efficiency are the main bottlenecks for their practical applications. Herein, a sequence of transition metals anchored on a novel category of transition metal dichalcogenides monolayers, Janus TMDs (TM@MoSSe, TM = Sc-Zn, Mo, W, Ru-Ag, and Os-Au), as NRR catalysts were investigated through a three-step detailed screening based on the density function theory (DFT) calculations. According to the estimated stability, high catalytic activity, and unexceptionable selectivity of TMDs, W@MoSSe and Os@MoSSe were identified as effective candidate catalysts for NRR, of which W@MoSSe was screened as the optimal NRR catalyst, and the limiting potential is -0.15 V. Importantly, W@MoSSe exhibits remarkable inhibition on the hydrogen evolution reaction (HER), due to the ultrahigh Faraday efficiency (100%). Notably, more density of states in W@MoSSe, apparent charge transfer, and strong orbital hybridization between W@MoSSe and NRR intermediates may contribute to its observed high NRR catalytic activity. These findings showed the feasible applications of Janus TMDs in the single-atom catalysis of the NH3 synthesis, which could open a new bright prospect for exploring efficient NRR catalysts experimentally.