Cobalt–Copper Single-Atom Alloy Catalyst for Electrochemical Nitric Oxide Reduction to Ammonia

Abstract

Abstract Electrochemical reduction of nitric oxide (NO) to ammonia (NH3) offers a more sustainable pathway. However, significant challenges remain in achieving high NH3 Faradaic efficiency, industrially relevant production rates, and downstream purification to meet commercial standards. Here, we report a cobalt–copper single-atom alloy (CoCu SAA) catalyst that has a remarkable NH3 production rate of 8995.9 μmol cm–2 h–1 in a flow cell and a current density of 1338.3 mA cm–2 with an NH3 Faradaic efficiency of 90.0%. Furthermore, the membrane electrode assembly (MEA) electrolyzer delivered an NH3 Faradaic efficiency of 91.8% at a current density of 3.0 A cm–2 and a cell voltage of 2.21 V. Electrochemical spectroscopic characterizations and density functional theory calculations reveal that isolated Co dopants optimize the adsorption strength of *NO and key reaction intermediates by modulating the electronic structure of neighboring Cu atoms, thus decreasing the energy barrier for the reaction and enhancing the catalytic activity and selectivity of NO electroreduction.