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

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 mu mol 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. (C) 2015 Elsevier B.V. All rights reserved.