Efficient Homojunction/Heterojunction Photocatalyst via Integrating CsPbBr 3 Quantum Dot Homojunction with TiO 2 for Degradation of Organic Dyes.

A novel TiO 2 -CsPbBr 3 (Q) photocatalyst is proposed and rationally constructed, where CsPbBr 3 perovskite quantum dots (QDs) of various sizes inside mesopore TiO 2 (M-TiO 2 ) are integrated. These perovskite QDs, generated in situ within M-TiO 2 , establish a type-II homojunction. Interestingly, a Z-scheme heterojunction is simultaneously formed at the interface between CsPbBr 3 and TiO 2 . Due to the coexistence of the type-II homojunction and the Z-scheme heterojunction, photogenerated electrons are effectively transferred from TiO 2 to CsPbBr 3 , thereby suppressing carrier recombination and thus enhancing the degradation of rhodamine B (RhB). Compared with pure CsPbBr 3 and TiO 2 , TiO 2 -CsPbBr 3 (Q) shows significantly enhanced photocatalytic performance for RhB degradation. The degradation efficiency of RhB in the presence of the TiO 2 -CsPbBr 3 (Q) attains 97.7% in 5 min under light illumination, representing the highest efficiency observed among photocatalysts based on TiO 2 . This study will facilitate the development of superior semiconductor catalysts for photocatalytic applications.