Novel TiO2 prepared from titanyl sulphate by using pressurized water processing and its photocatalytic activity evaluation

Abstract TiO 2 anatase was prepared by a novel preparation approach, combining utilization of titanyl sulphate as a precursor and pressurized water processing. In addition, two different chemical methods for preparation were used – thermal hydrolysis and induced hydrolysis. The photoactivity of developed TiO 2 was examined in two environmentally-prospective reactions: azo-dye AO7 photodiscoloration (oxidation) and N 2 O photodecomposition (reduction). It was revealed that during the processing the temperature has a crucial effect on TiO 2 crystallization contrary to pressure. TiO 2 anatase of smaller crystallite-size showed significantly higher photoactivity in AO7 photodiscoloration than TiO 2 anatase of large crystallite-size. However, in N 2 O photodecomposition all synthesized materials showed comparable activity. While the TiO 2 anatase crystallite-size and surface area are the determining properties in azo-dye AO7 photodiscoloration, the electronic band structure and recombination rate of electron and holes are determining in N 2 O photodecomposition. The correlation enabling the estimation of TiO 2 anatase crystallite-size from Raman FWHMs was found as well.