Boosting Nitrate‐to‐Ammonia Conversion over Copper‐Based Electrocatalysts by Facilitating Hydrogenation and Product Desorption

Abstract Electrocatalytic nitrate reduction reaction (NitRR) in neutral condition offers a sustainable route for ammonia (NH 3 ) production and water purification. For the most extensively investigated Cu‐based electrocatalysts that favor NO 3 − adsorption, insufficient hydrogenation capability and sluggish NH 3 desorption hinder the ultimate performance. Herein, we report Ca‐doped Cu 2 O co‐modified by oxalate (Ca─Cu 2 O─OA) as a novel and high‐performance NitRR electrocatalyst. Experimental and theoretical results demonstrate that the Ca dopant with strong hydration effect facilitates the hydrogenation steps of adsorbed NO 3 − on the adjacent Cu active sites. The hydrogen‐bonding interaction between OA and adsorbed NH 3 promotes the product desorption. Together with the strong NO 3 − adsorption capability and inhibited hydrogen evolution as a side reaction, excellent NitRR performance with a high Faraday efficiency (FE) of 97.49% and a high NH 3 yield of 15.02 mg h −1 cm −2 is achieved in neutral condition, outperforming most reported electrocatalysts. This work has provided new insights into the rational design of advanced NitRR electrocatalysts.