In situ-tuning lamellar bismuth-samarium catalysts for efficient CO2-to-formate electrosynthesis

Abstract

CO2 electroreduction enables the sustainable conversion of greenhouse gases into value-added chemicals, thereby reducing global warming. In this study, a bismuth–samarium (Bi–Sm) bimetallic catalyst (Bi4Sm1) was prepared, exhibiting excellent performance for the CO₂-to-formate electrosynthesis facilitated by situ-generated nanosheets. The incorporation of Sm into Bi catalyst enriched the active sites on the catalyst surface, achieving excellent stability (>150 h) and high formate selectivity (Faradaic efficiency, FEformate = 93.74 %) with a current density of 13.5 mA cm-2 at −1.0 V vs. reversible hydrogen electrode (VRHE) in a H-cell reactor containing 0.5 M KHCO3 electrolyte. Moreover, in a flow cell containing 1 M KOH electrolyte, the catalyst achieved a current density exceeding 162 mA cm-2 at -0.7 VRHE, with a slight decrease in FEformate (92.55 %). This catalyst outperformed most reported catalysts, highlighting its large-scale potential applications.