Tailoring Cu-Based Nanoalloys for Highly Selective Electrochemical Urea Synthesis from CO2 and Nitrate

The current carbon and nitrogen cycles, as driven by human activity, are characterized by high energy consumption, especially in the context of excessive CO2 emissions. To establish a commercially viable electrochemical coupling of nitrate and CO2 for urea production, developing a highly selective catalyst is crucial. In this study, we synthesized a series of ultrafine Cu-M (M = Bi, In, and Pb) nanoalloy catalysts using electrodeposition. We employed a phenanthroline-mediated approach to carefully control the dopant composition and nanoalloy size by regulating the electrodeposition kinetics. Our ultrafine Cu–Bi0.1 catalyst achieved a significantly enhanced Faradaic efficiency for urea production of 89.4% at −1.0 V vs RHE, compared to 41.5% for the Cu control. Operando Raman and Fourier-transform infrared spectroscopy provided compelling evidence supporting our catalytic findings. The remarkable selectivity to urea observed with our Cu–Bi0.1 catalyst originates from the stabilization of *CO and *NO2 intermediates. Through extensive theoretical calculations, we found that the presence of Bi in the Cu domain enhances urea formation both thermodynamically and kinetically. This work presents a promising chemical protocol for designing next-generation nanoalloy catalytic materials with enhanced properties.