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

Electrochemical conversion of nitrate (NO 3 – ) into ammonia (NH 3 ) recycles nitrogen and offers a route to the production of NH 3, which is more valuable than dinitrogen gas. However, today’s development of NO 3 – 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 3 – reduction reaction (NO 3 – RR) performance on Cu 50 Ni 50 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 d- band center and modulates the adsorption energies of intermediates such as *NO 3 –, *NO 2, and *NH 2 . Using density functional theory calculations, we identify a NO 3 – RR-to-NH 3 pathway and offer an adsorption energy–activity relationship for the CuNi alloy system. This correlation between catalyst electronic structure and NO 3 – RR activity offers a design platform for further development of NO 3 – RR catalysts.