Efficient N2 electroreduction enabled by linear charge transfer over atomically dispersed W sites†

Abstract

Electrocatalytic nitrogen reduction reaction (NRR) presents a sustainable alternative to the Haber–Bosch process for ammonia (NH₃) production. However, developing efficient catalysts for NRR and deeply elucidating their catalytic mechanism remain daunting challenges. Herein, we pioneered the successful embedding of atomically dispersed (single/dual) W atoms into V_2−xCT_yvia a self-capture method, and subsequently uncovered a quantifiable relationship between charge transfer and NRR performance. The prepared n-W/V_2−xCT_y shows an exceptional NH₃ yield of 121.8 μg h⁻¹ mg⁻¹ and a high faradaic efficiency (FE) of 34.2% at −0.1 V (versus reversible hydrogen electrode (RHE)), creating a new record at this potential. Density functional theory (DFT) computations reveal that neighboring W atoms synergistically collaborate to significantly lower the energy barrier, achieving a remarkable limiting potential (U_L) of 0.32 V. Notably, the calculated U_L values for the constructed model show a well-defined linear relationship with integrated-crystal orbital Hamilton population (ICOHP) (y = 0.0934x + 1.0007, R² = 0.9889), providing a feasible activity descriptor. Furthermore, electronic property calculations suggest that the NRR activity is rooted in d–2π* coupling, which can be explained by the “donation and back-donation” hypothesis. This work not only designs efficient atomic catalysts for NRR, but also sheds new insights into the role of neighboring single atoms in improving reaction kinetics.