Enhanced Nitrate-to-Ammonia Activity on Copper-Nickel Alloys via Tuning of Intermediate Adsorption.

Electrochemical conversion of nitrate (NO) into ammonia (NH) recycles nitrogen and offers a route to the production of NH, which is more valuable than dinitrogen gas. However, today's development of NO electroreduction remains hindered by the lack of a mechanistic picture of how catalyst structure may be tuned to enhance catalytic activity. Here we demonstrate enhanced NO reduction reaction (NORR) performance on CuNi alloy catalysts, including a 0.12 V upshift in the half-wave potential and a 6-fold increase in activity compared to those obtained with pure Cu at 0 V vs reversible hydrogen electrode (RHE). Ni alloying enables tuning of the Cu band center and modulates the adsorption energies of intermediates such as *NO, *NO, and *NH. Using density functional theory calculations, we identify a NORR-to-NH pathway and offer an adsorption energy-activity relationship for the CuNi alloy system. This correlation between catalyst electronic structure and NORR activity offers a design platform for further development of NORR catalysts.