Bi₂O₃ microspheres combined electron-deficient B-reduced graphene oxide as functional electrocatalyst for effective synthesis urea from N₂ and CO₂

Electrochemical synthesis urea, which couples N₂ and CO₂, is seen as a potential promising and sustainable alternative to traditional harsh industrial process. However, the significance of the rational design electrocatalyst has been enthused due to the hard activation of N≡N, the prevalence of sub-reactions, and the low current density. Herein, an electrocatalyst, Bi₂O₃/B-reduced graphene oxide (RGO) was prepared for synthesis urea with a Faraday efficiency (FE) of 12.8 %, urea yield of 9.2 mmol g⁻¹h⁻¹ and urea current density 0.47 mA cm⁻² at −0.8 V, while maintaining long-term stability. The Bi₂O₃/B-RGO possess a unique porous structure with continuous micron pores that facilitated the rapid mass transfer, improved kinetic efficiency and enlarged electroactive sites, which together improve the urea synthesis performance. Interestingly, the Bi₂O₃/B-RGO electrocatalyst is not only have excellent electrochemical properties, but also favours the adsorption and activation of reactants (N₂ and CO₂) due to the B-RGO (Lewis acid) and the Bi₂O₃ (Lewis base). This work may provide new insights into the exploration of advanced catalysts for electrochemical urea synthesis and other sustainable applications.