In@Mn ₃ O ₄ with Rich Interface Low‐Coordination Mn Active Sites for Boosting Electrocatalytic Nitrogen Reduction

Abstract Electrocatalytic nitrogen reduction reaction (NRR) is a potential strategy for green synthesis of ammonia. However, the lack of efficient catalysts with both high activity and high selectivity restricts the development of electrocatalytic NRR. In this study, a simple water‐based redox method is used to synthesize the core–shell nanoparticle catalyst with 2D Mn ₃ O ₄ nanoparticle as shell and In as core. The Mn ₃ O ₄ nanoparticle shell with rich interface low‐coordination Mn helps to provide more active sites for electrocatalytic NRR. At the same time, the In nucleus gives electrons to the Mn ₃ O ₄ nanoparticle shell, jointly promotes the adsorption and activation of nitrogen, as well as the enhancement of NRR activity. Moreover, the designed Mn ₃ O ₄ shell is hydrophobicity, which effectively reduces the side reaction of hydrogen evolution of H proton generated from water dissociation, and the selectivity of NRR is improved. In 0.1 m Na ₂ SO ₄ , the ammonia yield of In@Mn ₃ O ₄ is 89.44 µg h ⁻¹ mg _cat ⁻¹ (−0.9 V vs RHE) and the maximum Faradaic efficiency is 27.01% at −0.7 V (vs RHE), superior to most reported catalysts. The unique core–shell structure and the design of low Mn coordination provide unique insights for the regulation of the nitrogen–water interface environment and rational design of advanced NRR electrocatalysts.