Fabrication of CdS quantum dots sensitized TiO2 nanowires/nanotubes arrays and their photoelectrochemical properties

Abstract

Herein, CdS quantum dots (QDs) sensitized TiO2 nanowires/nanotubes arrays (CdS–TiO2 NWs/NTs) have been successfully fabricated through an optimized one-step anodization method, followed by successively ion layer adsorption and reaction strategy. The structures of the as-prepared samples were characterized by scanning electrons microscopy, X-ray diffraction and X-ray photoelectron microscopy. Results indicated that TiO2 NWs/NTs were comprised of well-ordered NTs arrays in the bottom and NWs at the mouth of the NTs. CdS QDs were uniformly adhered to the surface of the NWs, as well as inner walls of the NTs. In addition, optical and photoelectronchemical properties of the as-prepared samples were investigated. All results showed that CdS–TiO2 NWs/NTs exhibited excellent photoelectric and photocatalytic activities, a photocurrent density of 1.04 mA cm−2, a photocatalytic efficiency of degradation methyl blue of 97.8% after 120 min, and the rate of repeated degradation maintained at 95.8% after 5 cycles. A possible mechanism was described to lay the foundation for future applications.