Preparation of TiO2 microspheres with flower-like morphology through a water-in-oil emulsion route assisted by solvothermal treatment

Abstract Mesoporous TiO 2 microspheres with flower-like morphology, high specific surface area, and high-crystallinity primary crystalline-phase of anatase have been prepared through a water-in-oil emulsion synthesis route assisted by solvothermal treatment. The as-prepared powder microspheres, as well as their precursor, were characterized by various techniques. Thermogravimetry and differential thermal analysis indicated that the optimal sintering temperature of the TiO 2 precursor was 550 °C. Field emission scanning electron microscopy, laser particle size analysis, and X-ray diffraction jointly confirmed that the precursor powder with a spherical structure and main particle sizes ranging from 3 to 20 μm had the same primary crystalline-phase as the TiO 2 microspheres obtained from the calcination of the precursor at 550 °C for 4 h. The specific surface area of the TiO 2 microspheres was approximately 123.6 m 2 /g according to the Brunauer–Emmett–Teller (BET) nitrogen adsorption results. Compared with the commercial TiO 2 powder (P25), the resulting TiO 2 microspheres exhibited a higher photocatalytic activity. Based on the experimental results, a rational mechanism was proposed to elucidate the formation of the TiO 2 microspheres.