Regulating Local Electron Distribution of Cu Electrocatalyst via Boron Doping for Boosting Rapid Absorption and Conversion of Nitrate to Ammonia

Abstract The electrochemical reduction of nitrate to ammonia (NO 3 RR) is an effective route to ammonia synthesis with the characteristics of low energy input. However, the complex multi‐electron/proton transfer pathways associated with this reaction may trigger the accumulation of competitive by‐products. Herein, boron (B)‐doped Cu electrode (denoted as B–Cu 2 O/Cu/CP) as “all‐in‐one” catalyst is prepared by one‐step electrodeposition strategy. Caused by the B doping, the charge redistribution and local coordination environment of Cu 2 O/Cu species are modulated, resulting in the exposure of active sites on the Cu 2 O/Cu/CP catalyst. In‐situ Fourier transform infrared spectroscopy and theoretical investigations demonstrate that both Cu 2 O and Cu sites modulated by B can effectively enhance the adsorption of NO 3 − and facilitate the conversion of intermediate by‐products, thus promoting the direct reduction of NO 3 − to NH 3 . Consequently, a remarkable Faradaic efficiency of 92.74% can be obtained on B–Cu 2 O/Cu/CP catalyst with minimal accumulation of by‐products. It is expected that this work, based on the heterogeneous B doping, will open a maneuverable and versatile way for the design of effective catalysts.