Preparation of cobalt coated TiO2 and WO3-TiO2 nanotube films via photo-assisted deposition with enhanced photocatalytic activity under visible light illumination

Highly ordered TiO2 and WO3-TiO2 nanotubes were prepared by one-step electrochemical anodizing method and cobalt has been successfully deposited on these nanotubes by photo-assisted deposition process. The morphology, crystal structure, elemental composition and light absorption capability of samples were characterized by field emission scanning electron microscope, X-ray diffraction, energy dispersive X-ray spectrometer and ultraviolet visible spectroscopy methods. All cobalt loaded samples show an appearance of red shift relative to the unloaded samples. The degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of these novel visible-light responsive photocatalysts. Results showed that the photocatalytic activity of bare WO3-TiO2 samples is higher than that with undoped TiO2 sample. Compared with unmodified TiO2 and WO3-TiO2, the Co/TiO2 and Co/WO3-TiO2 samples exhibited enhanced photocatalytic activity in the degradation of methylene blue. Kinetic research showed that the reaction rate constant of Co/WO3-TiO2 is approximately 2.26 times higher than the apparent reaction rate constant of bare WO3-TiO2. This work provides an insight into designing and synthesizing new TiO2-WO3 nanotubes-based hybrid materials for effective visible light-activated photocatalysis. The catalysts prepared in this study exhibit industrially relevant interests due to the low cost and high photocatalytic activity. (c) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.