Electrochemical construction of different titania-tungsten trioxide nanotubular composite and their photocatalytic activity for pollutant degradation: a recyclable photocatalysts

摘要

Different TiO_2-WO_3 nanotubular (TWNs) electrodes were fabricated by in situ anodization of titanium in a single-step process using sodium tungstate as the tungsten source. The morphology and structure were characterized by field-emission scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spec-troscopy. Optical properties were investigated by ultra UV-Vis diffuse reflectance spectra. The resulting TWNs showed a tube diameter of 80-110 nm, wall thickness of 20-40 nm and tube lengths in the range of 7-8 μm. The visible light photocatalytic activity of the TWNs electrodes was evaluated by measuring the degradation of methylene blue dye under simulated sunlight conditions and compared with photo-catalytic activity of pure TiO_2 nanotubes (TNs). The results showed that TWNs electrodes have excellent photo-catalytic performance. The sample C, that formed by anodic oxidation in a DMSO electrolyte containing 4 g/l sodium tungstate, exhibited better photo-catalytic activity than the TNs and TWNs fabricated using other W concentrations under Xe illumination. The anodization process developed in this study is facile, reproducible, and inexpensive, and can be easily scaled up, thereby pioneering the fabrication of high performance photo-catalysts with promising environmental applications.