Boosting Electrocatalytic NO Reduction via Intermediate Adsorption Modulation on Synergistic CuCo Bimetallic Oxide Catalysts.

Cobalt-based catalysts are extensively employed in the electrocatalytic nitric oxide reduction reaction (NORR) for ammonia synthesis due to their superior ammonia selectivity. However, their practical implementation is significantly hindered by insufficient adsorption capacity toward NO and critical intermediates. To address this limitation, we strategically integrated copper (Cu) into a cobalt (Co) matrix through hydrothermal synthesis followed by controlled annealing, resulting in a well-dispersed CuCo bimetallic catalyst (CuCo3Ox-650). This catalyst exhibits exceptional electrochemical performance, delivering an NH3 generation rate of 312.1 μmol h-1 cm-2 at -0.5 V with a Faradaic efficiency (FE) of 90.8%. Density-functional-theory analysis indicates that Co atoms serve as the principal conduits for charge transfer during NO adsorption on CoCuO2, while Cu incorporation induces supplementary electron redistribution, upshifting the d-band center and strengthening the binding of NO and intermediates (e.g., *NHx). Remarkably, the adsorption energy of *H on CuCo3Ox-650 is merely 1/7 that for NO, effectively suppressing the competing hydrogen evolution reaction (HER) by minimizing parasitic *H accumulation. The synergistic interplay between Co and Cu optimizes both the activity and selectivity for NO-to-NH3 conversion. Furthermore, when a Zn-NO battery is operated with the cathode, CuCo3Ox-650 achieves a peak power density of 5.57 mW cm-2 and an ammonia production rate of 438.44 μg h-1 cm-2, showcasing its dual functionality in energy conversion and environmental remediation.