Effect of CdS shell thickness on the photocatalytic properties of TiO2@CdS core-shell nanorod arrays

Rutile TiO2 nanorod arrays (NRAs) with average diameter approximately 80 nm were first synthesized by solvothermal method using Ti foil as both titanium source and substrate. And then TiO2@CdS core-shell heterostructure NRAs were fabricated via subsequent successive ionic layer adsorption and reaction (SILAR) route using the TiO2 NRAs as precursor. The thicknesses of CdS shell varied from 4 to 18 nm by changing the times of SILAR cycle. The photocatalytic performances of pure TiO2 and all TiO2@CdS NRAs were investigated on the degradation of rhodamine B (RhB) aqueous solution under simulated sunlight irradiation. Compared to pure TiO2 NRAs, all TiO2@CdS NRAs displayed superior photocatalytic activities, and the optimal CdS shell thickness of TiO2@CdS NRAs was about 11 nm. A possible Z-scheme electron transfer mechanism for TiO2@CdS NRAs nanocomposite with the enhanced photocatalytic performance was provided.