Fabrication of mesoporous TiO2 with high crystallinity by a fast sol–gel method

Mesoporous TiO2 samples with high crystallinity were successfully synthesized by a fast sol–gel method using polyethylene glycol (PEG) and polyacrylamide (PAM) as dual templates using two-step calcining process. As a comparison, the sample was synthesized by traditional sol–gel method using hexadecyl trimethyl ammonium bromide as the template. The samples were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption–desorption, and diffuse reflectance UV–visible absorption spectra. The results showed that when samples were prepared at 500–700 °C in nitrogen atmosphere and 500 °C in air atmosphere, they exhibited typical mesoporous structure, large specific surface area and high crystallinity. The effects of PEG on properties of the samples and the effect of PAM on sol–gel reaction rate were studied. The results show that PAM accelerates gel rate and PEG increases specific surface area of samples. The crystallinity of the samples was increased by using two-step calcining process. Compared with sample synthesized by traditional sol–gel method, visible light response and photocatalytic activity of sample synthesized by the fast sol–gel method were improved.