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

Abstract

AbstractElectrocatalytic nitrate reduction reaction (NitRR) in neutral condition offers a sustainable route for ammonia (NH3) production and water purification. For the most extensively investigated Cu‐based electrocatalysts that favor NO3− adsorption, insufficient hydrogenation capability and sluggish NH3 desorption hinder the ultimate performance. Herein, we report Ca‐doped Cu2O co‐modified by oxalate (Ca─Cu2O─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 NO3− on the adjacent Cu active sites. The hydrogen‐bonding interaction between OA and adsorbed NH3 promotes the product desorption. Together with the strong NO3− 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 NH3 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.