An easy-to achieve approach for the fabrication of CdS QDs sensitized TiO2 nanotubes and their enhanced photoelectrochemical performance

In this work, we develop an original and easy-to-achieve experimental approach to produce CdS quantum dots (QDs) decorating TiO2 nanotubes (NTs) onto Ti sheets, by combining Ti anodization technique, CdS QDs polyol production and aqueous impregnation. The obtained films were characterized by Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and UV-visible Diffuse Reflectance Spectroscopy. The realized hetero-nanostructures were used as photoanodes in a photoelectrochemical (PEC) cell to evaluate their ability to oxidize water for hydrogen generation. An enhanced photocurrent density, J of 0.4 mA/cm(2) at 0V (vs. Ag/AgCl)) was measured when immersed in a Na2SO4 electrolyte aqueous solution and illuminated by a Xenon lamp. This value is about four times higher than that measured on their QDs free counterparts. The obtained results are very encouraging considering the very weak amount of grafted narrow band-gap nanocrystalline semiconductors, namely CdS QDs. Clearly, CdS QDs allow a wider solar light wavelength range absorption and a lower carrier electron-hole recombination, leading to a considerable improvement in the photoelectrochemical performances. (C) 2016 Elsevier B.V. All rights reserved.