Boosting Electrochemical Reduction of Nitrate to Ammonia by Constructing Nitrate‐Favored Active Cu–B Sites on SnS2

Abstract The electrochemical reduction of nitrate to ammonia is an effective method for mitigating nitrate pollution and generating ammonia. To design superior electrocatalysts, it is essential to construct a reaction site with high activity. Herein, a simple two‐step method is applied to in situ reduce amorphous copper over boron‐doped SnS 2 nanosheets(denoted as aCu@B–SnS 2‐x . DFT calculations reveal the combination of amorphous copper and B‐doping strategy can construct Cu–B active twins and introduce sulfur vacancies on the surface of the inert SnS 2 , the active twins can efficiently adsorb nitrate and forcibly separate oxygen atoms from nitrate under the assistance of the exposed Sn atom, leading to strong nitrate adsorption. Benefiting from this, aCu@B–SnS 2‐x exhibited an ultrahigh NH 3 FE of 94.6% at −0.67 V versus RHE and the highest NH 3 yield rate of 0.55 mmol h −1 mg −1 cat (9350 µg h −1 mg −1 cat ) at −0.77 V versus RHE under alkaline conditions. Besides, aCu@B–SnS 2‐x is confirmed to remain active after various stability tests, suggesting the practicality of utilizing aCu@B–SnS 2‐x in industrial applications. This work highlights the feasibility of enhanced nitrate‐to‐ammonia conversion efficiency by combining the doping method and amorphous metal.