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

Abstract

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.