Photodegradation of Unsymmetrical Dimethylhydrazine by TiO2 Nanorod Arrays Decorated with CdS Nanoparticles Under Visible Light

Photocatalysis technology could utilize solar energy to degrade many toxic pollutants and provides possibility to deal with unsymmetrical dimethylhydrazine (UDMH) wastewater with less energy consumption. In this study, well-aligned TiO2 nanorod arrays (TiO2 NRAs) were grown directly on transparent conductive glass (FTO) via a hydrothermal method, and TiO2 NRAs/CdS heterostructure films were prepared by decorating TiO2 NRAs with CdS nanoparticles through successive ion layer adsorption and reaction (SILAR). Under visible light, the TiO2 NRAs/CdS heterostructure displays enhanced photodegrading capacity compared with the bare TiO2 NRAs, and the highest photodegradation rate, 27.5% higher than that of the bare TiO2 NRAs, was achieved by the sample with 15 SILAR cycles. Additionally, the solution pH had some influence on the degradation process, which shows that the best degradation rate can be achieved in the neutral solution (pH is ca. 7.2), and the photodegradation process can be better in alkaline solution than in the acid solution. Moreover, the visible photocatalytic stability of the TiO2 NRAs/CdS sample was investigated. Finally, the underlying photocatalytic mechanism was discussed according to the photoelectrochemical and photoluminescence results.