FT-IR study of the photocatalytic degradation of gaseous toluene over UV-irradiated TiO2 microballs: enhanced performance by hydrothermal treatment in alkaline solution

▶ TiO2 microballs were obtained via a hydrothermal treating of commercial P25 in alkaline solution. ▶ A blue-shifted SPV threshold edge was observed for the TiO2 microballs. ▶ The TiO2 microballs were more active than P25 in photocatalytic oxidation of gaseous toluene. In this study, photocatalysts of TiO2 microballls were obtained via a hydrothermal treating of commercial P25 in alkaline solution, and then characterized with SEM, XRD, BET, DRS and surface photovoltage spectroscopy (SPS) techniques. The photovoltage response of the prepared TiO2 microballs on spectrum features a quantum size effect brought about by the reduced grain size with respect to the precursor. The UV-assisted photodegradation of gaseous toluene over P25 and the prepared TiO2 microballs was monitored by an in situ infrared technique. The results demonstrated that the prepared TiO2 microballs in anatase form were more active than commercial P25 in photocatalytic oxidation of gaseous toluene. The promoted activity of the hydrothermal-treated TiO2 is attributed to the increasing specific surface area and larger band gap induced by the reduced crystallite size.