Enhanced photocatalytic and photoelectrochemical properties of TiO2 nanorod arrays sensitized with CdS nanoplates

Abstract TiO 2 nanorod arrays (NRAs) sensitized with CdS nanoplates (NPLs) were fabricated via a two-step method. Vertically aligned TiO 2 NRAs were synthesized by a hydrothermal method, and followed by depositing CdS NPLs on TiO 2 NRAs via successive ion layer absorption and reaction (SILAR) method. Their surface morphology, structure, photoelectrochemical, and photocatalytic properties were investigated. UV-via absorption spectra suggest that the absorption peaks shift from the ultraviolet region (408 nm) to the visible region (580 nm) when compared to pure TiO 2 nanorod arrays. Additionally, upon irradiation of visible light, the photocurrent response of CdS NPL sensitized TiO 2 NRAs after 8 SILAR cycles significantly improved, displaying an optimal photocurrent density of 168.5  μ A /cm 2 , which is much higher than that of the unsensitized samples (48.1  μ A /cm 2 ). They also exhibited excellent photocatalytic properties where the degradation rate of methyl orange under visible light showed an enhancement of 92.4% compared to bare TiO 2 NRAs. The mechanisms of the enhanced photocatalytic and photoelectrochemical properties of TiO 2 nanorod arrays sensitized with CdS nanoplates are discussed in detail.