Spectroelectrochemical insight into copper cobalt catalysts for CO2 and nitrite co-electroreduction to urea

Electrochemical CO2 and nitrite co-reduction provides a sustainable urea synthesis route but remains limited by low selectivity and an undecided C–N coupling mechanism. Here, we report co-sputtered bimetallic Cu–Co catalysts that facilitate urea formation via a tandem relay mechanism. The optimal Cu:Co ratio of 1:1 achieves a urea yield rate of 61 ± 6 mmol h⁻1gcat⁻1 at –1.2 V vs. RHE under neutral pH, emphasizing the importance of proton balance in sustaining proton-coupled electron transfer. In situ synchrotron-based infrared and Raman spectroscopy monitor the dynamic evolution of *CO, *NH2, and C‒N intermediates. In situ X-ray absorption spectroscopy indicates the structural stability of metallic Cu and Co active sites. Density functional theory calculations suggest that *COOH + *NH2 coupling initiates urea pathway, with *NH2CO formation as the potential-determining step. This study integrates rational catalyst design and in situ spectroelectrochemical analysis to advance understanding of electrochemical C–N coupling for urea synthesis. Electrochemical conversion of CO2 and nitrite offers a green route to produce urea. Here, the authors report co-sputtered copper cobalt catalysts enable efficient C–N coupling through a tandem mechanism, yielding 61 mmol h⁻1gcat⁻1 urea at –1.2 V vs. RHE.