Unraveling the enhanced urea selectivity in electroreduction of CO2 and nitrate over Bimetallic CuZn catalysts

Abstract

Urea electrosynthesis plays a vital role in the nitrogen cycle, promoting carbon neutrality while also being energy-efficient. However, the complexities involved in the simultaneous of carbon and nitrogen-containing species significantly hinder the selectivity and yield of urea. In this study, we report a CuZn bimetallic catalyst that is capable of converting CO₂ and NO₃^⁻ into urea, with a maximum Faraday efficiency of 40% at -0.6 V vs. RHE, alongside an impressive urea yield rate of 304.8 mmol h^⁻¹ g_cat^⁻¹ at -0.9 V vs. RHE, surpassing the performance of both monometallic Cu and Zn catalysts. In situ spectroscopic analysis demonstrates that the Cu sites within CuZn facilitates the adsorption and activation of CO₂ and NO₃^⁻, while Zn sites additionally facilitate CO₂ adsorption and reduces the adsorption strength of *CO and *NH₂ on the catalyst surface, collectively promoting the formation of *CONH₂ as a key intermediate in urea synthesis. This study highlights the unique role of zinc in urea synthesis, offers new insights into optimizing the performance of copper-zinc catalysts, and serves as a valuable reference for future research on the role of zinc in urea synthesis.