Electrochemical co-reduction of N2 and CO2 to urea using In2S3 anchored on S-doped reduced graphene oxide

Abstract

The generation of urea by electrocatalysis using N2 and CO2 as feedstock is considered as a promising and green sustainable alternative to conventional energy-consuming industrial processes. Based on the existing studies, it was found that the effective adsorption and activation of N2 and CO2 on the catalyst surface is the primary condition for electrocatalytic generation, while the main by-product hydrogen evolution reaction (HER). Should be avoided as much as possible in order to improve the yield. In this paper, an In2S3-loaded electrocatalyst on sulfur-doped reduced graphene oxide for urea synthesis was designed and prepared with an average Faraday efficiency (FE) of 37.17 % and a urea yield of 7.24 mmol h−1 g−1, while maintaining long-term stability. In2S3@S-RGO has a unique porous structure of doped graphene, with continuous micron-sized pores that facilitate fast mass transfer, improve kinetic efficiency, and expand electroactive sites, thus enhancing the urea synthesis performance. Interestingly, the In2S3@S-RGO electrocatalyst not only exhibits excellent electrochemical performance, but also facilitates the adsorption and activation of reactants (N2 and CO2) due to the inhibitory effect of the indium-based material on HER. This work may provide new ideas for advanced catalysts to improve the efficiency of electrochemical synthesis of urea Faraday and to facilitate CN coupling applications.