Two‐dimensional Boridene Nanosheets for Efficient Electrochemical Nitrogen Fixation under Ambient Conditions

Abstract The carbon‐free electrocatalytic nitrogen reduction reaction (NRR) is an alternative technology to the current Haber‐Bosch method, that can be conducted under ambient conditions, and directly converting water and nitrogen (N₂) into ammonia (NH₃). However, the limited activity and selectivity of NH₃ electrosynthesis hinder the practical applications of NRR. In this study, we present a novel type of electrocatalyst called boridene nanosheets enriched with metal vacancies that are specifically designed for efficient electrocatalytic NRR under ambient conditions. Electrochemical testing in a 0.1 M phosphate‐buffered saline (PBS) electrolyte demonstrates that boridene exhibits a high Faradaic efficiency of 66.7 % for NH₃ production at −0.2 V vs. RHE, with a maximum NH₃ yield rate of 23.6 μg h −1 mg cat −1 at −0.4 V vs. RHE. Durability tests show that boridene maintains significant stability throughout multiple cycles of NRR. Mechanistic insights are obtained through in situ Fourier transform infrared spectroscopy, revealing that boridene exhibits a preference for the distal pathway during the process of NRR. These findings highlight the potential of boridene as an efficient and stable catalyst for sustainable NH₃ synthesis.