Synergistic boron-dopants and boron-induced oxygen vacancies in MnO₂ nanosheets to promote electrocatalytic nitrogen reduction

The development of highly efficient and durable electrocatalysts for the nitrogen reduction reaction (NRR) is of paramount significance for NH₃ electrosynthesis. Herein, we report an effective B-doping strategy for the structural engineering of MnO₂ toward the NRR through combined experimental and theoretical studies. Introducing B-dopants into MnO₂ nanosheets was found to create abundant O-vacancies which cooperated with B-dopants to promote the conductivity and enhance the intrinsic NRR activity of MnO₂. The developed B-doped MnO₂ nanosheets grown on carbon cloth (B-MnO₂/CC) exhibited a significantly enhanced NRR performance with an NH₃ yield of 54.2 μg h⁻¹ mg⁻¹ (−0.4 V) and a faradaic efficiency of 16.8% (−0.2 V), and are among the best Mn-based NRR catalysts reported so far. Density functional theory calculations further revealed the synergistic role of B-dopants and O-vacancies in inducing asymmetric charge distribution, which could activate the neighboring Mn atoms to facilitate the stabilization of the key intermediate *N₂H on MnO₂, leading to reduced reaction energy barrier and enhanced intrinsic NRR activity.