Nanocrystalline anatase TiO2 photocatalysts prepared via a facile low temperature nonhydrolytic sol-gel reaction of TiCl4 and benzyl alcohol

Abstract Nanocrystalline anatase TiO 2 photocatalysts prepared by a facile nonhydrolytic sol–gel (NSG) reaction of TiCl 4 and benzyl alcohol at low temperature, followed by subsequent calcination at elevated temperatures were investigated in relation to their performance in the photocatalytic degradation of phenol. A variety of techniques including N 2 adsorption, X-ray powder diffraction (XRD), diffuse reflectance FTIR spectroscopy (DRIFTS), thermogravimetric measurements (TG/DTA), transmission electron micrographs (TEM), and X-ray photoelectron spectroscopy (XPS) were employed to characterize the resulting materials. It is shown that the fresh nanocrystalline TiO 2 sample obtained by the low temperature NSG process exhibits considerable activity comparable to that of commercial photocatalyst Degussa P-25, although evidence shows it to be surface-capped with appreciable amount of organic moieties. Moreover, it is demonstrated that the catalytic efficiency of the as-prepared nanocrystalline TiO 2 sample can be further markedly enhanced by subsequent thermal treatment at elevated temperatures ranging from 300 to 600 °C. Both the calcination temperature and calcination time appear to be crucial factors in influencing a number of critical properties of the calcined TiO 2 samples such as the surface area, particle size, crystallinity, amount of surface hydroxyl groups, as well as carbonaceous residues. The TiO 2 photocatalyst obtained by calcination at 400 °C for 3 h exhibits the highest activity toward photocatalytic degradation of phenol.