Crystal-Facet Modulated Pathway of CO2 Photoreduction on Bi4NbO8Cl Nanosheets Boosting Production of Value-Added Solar Fuels

Abstract

Two ultrathin nanosheets of Bi4NbO8Cl were successfully synthesized for photocatalytic conversion of CO2 into solar fuel. featuring differently exposed (001) and (201) facets. In contrast to bulk Bi4NbO8Cl, which produced only CO, both BNOC-(001) and BNOC-(201) demonstrated approximately 11 times greater CO evolution yield. Excitingly, these two nanosheets also generated ethanol with selectivities of 8.2% and 33.4%, respectively. It suggests that the exposure of specific facets of BNOC can enhance C-C coupling to form C2 species, with (201) facet typically accelerating this process. In contrast with (001) facet, the more low-coordinated Nb atoms exposed on (201) serve as capture sites for photogenerated electrons and catalytic sites for CO2, while also reducing competing CO production reactions by lowering the energy barriers for C-C coupling and the adsorption energy of the *COCOH intermediate.