Unique S-scheme heterojunctions in self-assembled TiO/CsPbBr hybrids for CO photoreduction.

Exploring photocatalysts to promote CO photoreduction into solar fuels is of great significance. We develop TiO/perovskite (CsPbBr) S-scheme heterojunctions synthesized by a facile electrostatic-driven self-assembling approach. Density functional theory calculation combined with experimental studies proves the electron transfer from CsPbBr quantum dots (QDs) to TiO, resulting in the construction of internal electric field (IEF) directing from CsPbBr to TiO upon hybridization. The IEF drives the photoexcited electrons in TiO to CsPbBr upon light irradiation as revealed by in-situ X-ray photoelectron spectroscopy analysis, suggesting the formation of an S-scheme heterojunction in the TiO/CsPbBr nanohybrids which greatly promotes the separation of electron-hole pairs to foster efficient CO photoreduction. The hybrid nanofibers unveil a higher CO-reduction rate (9.02 μmol g h) comparing with pristine TiO nanofibers (4.68 μmol g h). Isotope (CO) tracer results confirm that the reduction products originate from CO source.