Synthesis Of Ordered Mesoporous TiO₂

Mesoporous TiO2 has been widely used in many areas, attributed to its good thermal stability, high specific surface area, ordered pore structure, adjustable pore size within a certain range and modificated surface, which can effectively enhance its photocatalytic, photovoltaic conversion functions. So mesoporous TiO2 demonstrate a broad application prospects in water treatment, air purification, solar cells, nano-materials, micro-reactor, bio-materials, etc.The synthesis of pure mesoporous titania is difficult, because of the fast rate hydrolysis and condensation of titanium source, which is difficult to contronl. As well as the pore structure were easily to collapse during calcination process of crystals. So the key factors of obtained well-ordered mesorporous TiO2 are how to control the rate of hydrolysis and condensation of titanium source, and how to maintain the order of pore walls structure in calcination process.Mesoporous TiO2 was synthesized via Solvent evaporation-induced self-assemly method (EISA) with tetra butyl titanate ester as titanium source. Acetyl acetone was added to control the rate of hydrolysis and condensation of titanium source. The synthesis conditions were investigated such as the type of template, calcination temperature, molar ratio of water and titanium source, and molar ratio of template and titanium source. The obtained material were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption. Thermogravimetric-differential thermal analysis (TG-DTA). The results were showed as follows:1. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)(P123) is the best template in various types of templates, the well-ordered mesoporous structure TiO2 were obtained by using P123 as template.2. The optimal calcination temperature is 350℃, the material can maintain its pore structure during calcination.3. The optimal molar ratio of water and titanium is 16:1, the larger surface area and the smaller average pore size TiO2 can be obtained.4. The TiO2 with large surface area and ordered mesoporous was get when the molar ratio of P123 and titanium is 0.013.5. Mesoporous titania was obtained by EISA instead of hydrothermal method.