Tailoring Cu-based nanoalloys for highly selective electrochemical urea synthesis from C0₂ and nitrate

Abstract

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.