CsPbBr₃@TiO₂ Core-shell Structure Nanocomposite as Water Stable and Efficient Visible-light-driven Photocatalyst

The inherent poor stability of CsPbBr 3 perovskite quantum dots (QDs) is the main impediment restricting their applications. In this work, a CsPbBr 3 @TiO 2 core-shell structure nanocomposite with high water stability and efficient photocatalytic activity was fabricated through the hydrolysis of tetrabutyl titanate, followed by calcination. The as-prepared CsPbBr 3 QDs have a size of ca. 8 nm, encapsulated by incompletely crystallized TiO 2 protective layer with a thickness of ca. 20 nm. The photocatalytic performance of the CsPbBr 3 @TiO 2 nanocomposite was investigated by degradation of Rhodamine B (RhB) in water under visible light irradiation. The result shows that the CsPbBr 3 @TiO 2 nanocomposite exhibits much more enhanced photocatalytic activity than pure TiO 2 and CsPbBr 3 perovskite quantum dots. The photocurrent test results showed that the formation of the CsPbBr 3 @TiO 2 heterostructure can promote the separation of photogenerated carriers, which led to the improvement of photocatalytic performance of the composite material. More importantly, TiO 2 can act as a protective layer