Succulent-like core–shell composite: Synthesis of CdS coated with an ultrathin layer of TiO2 and enhanced photocatalytic performance in the degradation of crystal violet and hydrogen production

Abstract A core–shell composite CdS-APS@TiO2 (APS = 3-aminopropyltriethoxysilane) has been prepared by a temperature-programmed hydrothermal method combined with a simple and convenient chemical bath deposition. The form of the product resembles that of a succulent plant. Electrostatic interaction between the water-stable TiO2 precursor with negative charge and the amino-functionalized petal-like surfaces of CdS is evident. The as-prepared composite adopts the aforementioned succulent morphology with a petal-like structure, surface-coated with TiO2. Moreover, compared with the CdS precursor, the specific surface area of the as-prepared CdS-APS@TiO2 composite is increased, and its optical absorption extends into the visible region. The CdS-APS@TiO2 composite shows high activity in multiple photocatalytic processes, and some activity in photocatalytic hydrogen production (149.2 μmol/g, 8 h). To assess its mode of action, trapping experiments have been carried out by adding various radical scavengers. Possible mechanisms for the photocatalytic degradation of dyes and the photocatalytic splitting of water over the CdS-APS@TiO2 composite are proposed.