Interfacial engineering of CeO2/Bi19Br3S27 heterojunction for efficient photoreduction of CO2 to CO with nearly 100% selectivity

Artificial photosynthesis, harnessing solar energy to convert CO 2 into hydrocarbons, holds great promise as a solution to climate change and energy scarcity. However, highly efficient CO 2 reduction reactions and selective activity carried out through photocatalysis using solar light remain a significant challenge. To tackle this issue, an interface engineering was employed to design a diatomic connection S-scheme heterojunction CeO 2 /Bi 19 Br 3 S 27 , featuring interface coupling effect. The optimized CeO 2 /Bi 19 Br 3 S 27 -20 achieves CO product unprecedented yield of 65.1 ​μmol ​g −1 ​h −1 with high selectivity (almost 100%) and an excellent stability under gas-solid catalysis, solar irradiation and cost-effective conditions without photosensitizer, sacrificial agent, rare element, noble metal cocatalyst, or high-pressure gaseous CO 2 . Combined experimental characterization and density functional theory (DFT) calculations elucidate the dual role of the engineered interface: (i) facilitating spatially directed charge separation through the S-scheme mechanism ascribed from the diatomic connection of Bi-O and Ce-S as well as the interface coupling effect, and (ii) lowering the energy barrier for ∗COOH intermediate formation while disfavoring ∗CHO pathways. This interfacial electronic restructuring promotes both CO 2 activation kinetics and thermodynamic selectivity towards CO. This work provides an innovative strategy of interfacial regulation for developing S-scheme heterojunction, simultaneously addressing the critical challenges of activity and selectivity in artificial photosynthesis. The diatomic connection S-scheme heterojunction, CeO 2 /Bi 19 Br 3 S 27 -20, achieves unprecedented high CO yield of 65.1 ​μmol ​g −1 ​h −1 with ∼100 ​% selectivity and excellent stability under gas-phase solar irradiation, and cost-effective conditions without photosensitizer, sacrificial agent, rare element, noble metal cocatalyst or high-pressure gaseous CO 2 . The engineered interface facilitates spatially directed charge separation through the S-scheme mechanism ascribed from the diatomic connection of Bi-O and Ce-S as well as the interface coupling, and lowers the energy barrier for ∗COOH intermediate formation while disfavoring ∗CHO pathways.