Electrochemical Nitrate Reduction to Ammonia on CuCo Nanowires at Practical Level

Abstract

Electrochemical reduction of nitrate (NO3RR) holds great promise for environmentally friendly ammonia production. Tandem catalysis is a promising strategy for boosting the NO3RR and inhibiting side effects, but it is still challenged by lacking well‐designed catalysts to drive this catalytic process. Herein, the study develops the CuCo branched nanowires (CuCo NW) catalyst, which efficiently converts NO3 − to NH3 on Co (111) and Cu (111) crystal facets through a tandem catalysis mechanism. The in situ grown CuCo NW on Cu foam demonstrates a remarkable Faraday efficiency of 90.3% at 1.0 A cm−2 and maintains stable operation for 200 h at 100 and 200 mA cm−2 in a flow reactor. Density functional theory calculations suggest that the initial absorption and subsequent deoxygenation of *NO3 on Co (111) leading to the formation of *NO2, followed by its transfer to Cu (111) and further conversion to *NH3, establish an optimal pathway by managing rate‐determining steps on individual surfaces for NO3RR. To showcase the practical application of the catalyst, the study further develops a scaling‐up prototype reactor for continuous ammonia production, realizing the gram‐level yield rate of 1474.09 mg h−1 and Faraday efficiency of 91.26% at practical‐level 20.0 A.