High Transmitance and High Activity of Modified Tio2 Sol(3/3)

In the past decade in this lab, we have developed a peroxy method to prepare TiO2 sol by using H2O2 as the agent for poly-condensation and crystallization of Ti(OH)4. The advantages of this sol are (i) it is in neutral, instead of acidic condition, it can be coated on any substrate; (ii) the shape is rhombus, it has high aspect ratio; (iii) the particles have nano-size; (iv) it has anatase structure after preparation, therefore it does not need annealing process; (v) it does not need surfactant in sol and is very stable even after several years. However, it still has some disadvantages: (i) the solid content is low; (ii) the activity is not high enough, especially in visible light range; (iii) it cannot prevent sodium migration from glass, sodium can cause decay of the activity of TiO2; (iv) the transmittance of TiO2 film on glass is not high enough. In other words, the anti-refraction property is not high enough. The objective of this study is to overcome the disadvantages of TiO2 sol. This project will be carried out in 3 years. In the first year, we will study on Photocatalytic Properties of SiO2-TiO2 Binary Oxide. Firstly, the optimal condition of sol preparation will be investigated by varying the heating time of the sols, and the samples will be characterized by SEM, TEM, HRTEM, XRD, UV-vis and XPS. The as-prepared sol will be coated on glass substrate by dip coating or spin coating. After that, the transmittance of TiO2 films will be examined by UV-vis spectrophotometer and the electronic structure of Ti and O will be examined by XPS. In addition, the photocatalytic activity of SiO2-TiO2 thin film on glass will be tested by photocatalytic degradation of methylene blue in water and ethanol (VOC) degradation under UVA or UVC light irradiation. In the 2nd year, we will study on sodium suppression of SiO2-TiO2 binary Oxide. In the 3rd year, vanadium, tungsten, and/or Ag, Cu cocatalysts will be introduced to TiO2 in order to narrow the band gap energy of TiO2 and allow the photocatalytic activity to occur under visible light region by using our preparation method.