Ampere-level current density ammonia electrochemical synthesis using CuCo nanosheets simulating nitrite reductase bifunctional nature

The development of electrocatalysts capable of efficient reduction of nitrate (NO(3)(−)) to ammonia (NH(3)) is drawing increasing interest for the sake of low carbon emission and environmental protection. Herein, we present a CuCo bimetallic catalyst able to imitate the bifunctional nature of copper-type nitrite reductase, which could easily remove NO(2)(−) via the collaboration of two active centers. Indeed, Co acts as an electron/proton donating center, while Cu facilitates NO(x)(−) adsorption/association. The bio-inspired CuCo nanosheet electrocatalyst delivers a 100 ± 1% Faradaic efficiency at an ampere-level current density of 1035 mA cm(−2) at −0.2 V vs. Reversible Hydrogen Electrode. The NH(3) production rate reaches a high activity of 4.8 mmol cm(−2) h(−1) (960 mmol g(cat)(−1) h(−1)). A mechanistic study, using electrochemical in situ Fourier transform infrared spectroscopy and shell-isolated nanoparticle enhanced Raman spectroscopy, reveals a strong synergy between Cu and Co, with Co sites promoting the hydrogenation of NO(3)(−) to NH(3) via adsorbed *H species. The well-modulated coverage of adsorbed *H and *NO(3) led simultaneously to high NH(3) selectivity and yield.