Electrochemical Reduction of Nitrate to Ammonia on Transition‐Metal Sputtered Copper Foams

The electrochemical nitrate reduction to ammonia (eNO 3 RR) is an important step toward sustainable ammonia synthesis. Despite a few challenges in securing sufficient nitrate sources for commercial scale production of ammonia, a key current focus is the search for a cost‐effective yet highly active catalyst. Here, we present physical vapor deposition as a quick and straightforward technique for producing a thin layer of cobalt deposits on copper foam which shows significant performance (95% FE NH3 ) for eNO 3 RR. The superior performance of the Co–Cu foam is proposed to arise from the synergistic impact of Co–Cu on the direct reduction of NO 3 − to NH 3 , coupled with the subsequent reduction of NO 2 − produced on Cu sites.