Anchoring Mo Single-Atom Sites on B/N Codoped Porous Carbon Nanotubes for Electrochemical Reduction of N₂ to NH₃

Electrochemical N₂ reduction reaction (ENRR) at ambient temperature is a futuristic method for the artificial synthesis of ammonia, but it is still not efficient enough to be applied on a large scale. Inspired by the molybdenum-containing nitrogen-fixing enzymes of rhizobia in nature, single Mo sites are predicted to serve as an effective catalyst for ENRR. Herein, B/N codoped porous carbon nanotube-supported single Mo site catalysts (Mo/BCN) were rationally designed and synthesized. Mo/BCN exhibits the highest catalytic activity toward N₂ fixation to NH₃ with a yield rate of 37.67 μg h^–1 mg_cat^–1 and a faradaic efficiency of 13.27% in 0.1 M KOH, which is better than those of nonprecious metal electrocatalysts. Density functional theory and extended X-ray absorption fine structure analysis indicated that single-atom Mo sites could be anchored on BCN nanotubes and act as sufficient active sites for nitrogen reduction. The present work may provide a theoretical and experimental strategy for developing efficient single-atom catalysts for ENRR.