Efficient Homojunction/Heterojunction Photocatalyst via Integrating CsPbBr3 Quantum Dot Homojunction with TiO2 for Degradation of Organic Dyes

A novel TiO₂-CsPbBr₃(Q) photocatalyst is proposed and rationally constructed, where CsPbBr₃ perovskite quantum dots (QDs) of various sizes inside mesopore TiO₂ (M-TiO₂) are integrated. These perovskite QDs, generated in situ within M-TiO₂, establish a type-II homojunction. Interestingly, a Z-scheme heterojunction is simultaneously formed at the interface between CsPbBr₃ and TiO₂. Due to the coexistence of the type-II homojunction and the Z-scheme heterojunction, photogenerated electrons are effectively transferred from TiO₂ to CsPbBr₃, thereby suppressing carrier recombination and thus enhancing the degradation of rhodamine B (RhB). Compared with pure CsPbBr₃ and TiO₂, TiO₂-CsPbBr₃(Q) shows significantly enhanced photocatalytic performance for RhB degradation. The degradation efficiency of RhB in the presence of the TiO₂-CsPbBr₃(Q) attains 97.7% in 5 min under light illumination, representing the highest efficiency observed among photocatalysts based on TiO₂. This study will facilitate the development of superior semiconductor catalysts for photocatalytic applications.