In-situ producing CsPbBr3 nanocrystals on (001)-faceted TiO2 nanosheets as S­scheme heterostructure for bifunctional photocatalysis.

Fabricating a cost-effective yet highly active photocatalyst to reduce CO2 to CO and oxidize benzyl alcohol to benzaldehyde simultaneously, is challenging. Herein, we construct an S-scheme 0D/2D CsPbBr3/TiO2 heterostructure for bifunctional photocatalysis. An in-situ synthetic route is used, which enables the precise integration between CsPbBr3 nanocrystals and ultrathin TiO2 nanosheets exposed with (001) facets (termed as TiO2-001), resulting in a tightly coupled heterointerface and desirable band offsets. The as-prepared CsPbBr3/TiO2-001heterojunctions exhibit boosted charge carrier kinetics, particularly, quick carrier separation/transfer and efficient utilization. Experimental results and theoretical calculations validate the S-scheme route in CsPbBr3/TiO2-001, which allows the enrichment of strongly conserved electrons-holes at conduction and valence bands of CsPbBr3 and TiO2-001, respectively. Consequently, compared to its counterparts, an excellent bifunctional activity (with 24 h reusability) is realized over CsPbBr3/TiO2-001, where the production rate of CO and benzaldehyde reach up to 78.06 µmol g-1h-1 and 1.77 mmol g-1h-1 respectively, without employing any sacrificial agents. This work highlights the development of perovskite-based heterostructures and describes the efficient harnessing of redox potentials and charge carriers towards combined photocatalytic systems.