Abstract
Titanium dioxide, known as one of the most efficient photocatalytist materials, is widely used because of its long-term stability, free from toxicity and good photocatalytic activity. This study is focused on the properties of metal-doped TiO2 nanobelts grown with hydrothermal treatment and ion-exchange. High yield, uniform tungsten-doped and VO2-modified TiO2 nanobelts were synthesized through the two-step synthesis. The growth parameters such as the structure of raw material, the nature and concentration of alkaline solution, reaction temperature and time are optimized depending on different doping source. In addition, the preparation of tungsten-doped TiO2 nanobelts was conducted with a one-step synthesis process combining ion-exchange with hydrothermal treatment. The influences of different amount of doping source on the growth and phases of tungsten-doped TiO2 were investigated. Ultraviolet–visible (UV–Vis) diffuse reflectance spectra of prepared metal-doped TiO2 were recorded. The doped TiO2 nanobelts possess narrower band gaps than the pure TiO2 nanobelt, which can be attributed to the enhanced absorption in the visible light region. The gas sensing properties to ethanol were demonstrated in this work. The electrical response towards different gas concentration have been tested at 150 °C. Doping effects on structural and sensing properties were also investigated. The tungsten-doped TiO2 nanobelts was found to possess a higher sensitivity than pure TiO2 thin film. Furthermore, the tungsten-doped TiO2 nanobelts exhibited a short response and recovery time at the relative low working temperature.