Solvothermal synthesis of mesoporous TiO2 microspheres and their excellent photocatalytic performance under simulated sunlight irradiation

TiO2 nanomaterials have been extensively studied as photocatalysts, in which mesoporous TiO2 microspheres would be good candidates for abatement of organic pollutants in waste water on account of their high photocatalytic activities and easily reclaiming. Here, mesoporous TiO2 microspheres were synthesized by a facile solvothermal method and characterized. The formation mechanism of the TiO2 microspheres was investigated based on series of control experiments. The photocatalytic activities of the as-prepared TiO2 microspheres were evaluated by photodegradations of methyl orange (MO) and phenol aqueous solutions, respectively, under simulated sunlight irradiation, and compared with those of commercial TiO2 (P25). The TiO2 microspheres exhibit excellent photodegradation activities on both MO and phenol, comparing to P25. For the two model pollutants, the photodegradation percentages by the TiO2 microspheres are both more than twice of those by P25 in the same condition. Moreover, it can quickly settle down mostly (>90%) in 20 min from the photocatalytic reaction mixture under gravity after stopping stirring and be reclaimed easily. Thus it could be a promising photocatalyst for waste water treatment.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 100–200 nm of TiO2 microspheres with a primary crystal size of 12.1 nm ► High BET specific surface area (118.3 m2 g−1) with hierarchical mesopores. ► Strong light harvesting capability and low recombination rate of electron and holes. ► Excellent photocatalytic activities on methyl orange and phenol, easily reclaiming. ► Large scale synthesis in mild condition with a facile method.