Visible light induced photocatalysis on CdS quantum dots decorated TiO2 nanotube arrays

• CdS-TNTAs was facilely synthesized by SILAR method with well dispersion of CdS QDs.
• CdS-TNTAs shows tunable absorption by controlling the loaded CdS QDs quantity.
• CdS(15)-TNTAs exhibits highest visible-light Rh B degradation and H2 generation.
• CdS-TNTAs photocatalysts can be easily recycled and have good stability.
• The mechanism of visible-light induced photocatalysis on CdS-TNTAs was proposed.

CdS quantum dots (QDs) have been successfully deposited on TiO2 nanotube arrays (TNTAs) by successive ionic layer adsorption and reaction (SILAR) method for visible-light-driven hydrogen production and organic compound degradation. The composition, morphology and optical property have been characterized by the X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–vis absorption spectra. The loading amount of CdS can be adjusted by controlling the deposition cycles which demonstrates correspondingly optical behaviors. CdS-TNTAs sample prepared by SILAR deposition with 15 cycles gives the highest hydrogen production rate of 1.89 μmol h−1 cm−2 for 15 mL solutions and the highest degrading rate. Moreover, a transfer mechanism of photo-generated electrons on CdS-TNTAs during the visible-light photocatalytic process is proposed based on the experimental analysis. Furthermore, the prepared sample has good stability and can be more easily reused than the powder catalyst.

The graphical abstract exhibits the schematic illustration of H2 generation on CdS-TNTAs. It shows QDs are uniformly deposited along nanochannels. The charge transfer route and related redox reaction are displayed once CdS-TNTAs are under visible light (>420 nm) irradiation.Figure optionsDownload high-quality image (186 K)Download as PowerPoint slide