Design of titania porous films controlled by precursors’ viscosity for photocatalytic application

Porous transparent films of TiO 2 (anatase) were obtained by controlled hydrolysis of titanium tetraisopropoxide (sol-gel method) in the presence of a polyethylene glycol as a template agent with molar masses of 300, 600 and 1000 g/mol and α-terpineol as a high viscosity agent. The efficiency of the films in the photocatalytic degradation of Rhodamine 6G is correlated with their porosity and films’ thickness. Higher photoactivity of the obtained films compared with a non-porous TiO 2 film was observed for TiO 2 (300) and TiO 2 (600) whereas the lower activity was noted for TiO 2 (1000). The size of anatase crystals is increased proportionally to the precursor’ gelation time and is accompanied by a decrease of the specific surface area and porosity of the film. The presence of polyethylene glycol slowed down TIPT’s hydrolysis rate. It is shown that the viscosity of the precursor is the key factor in the preparation of titania films with certain crystal size, thickness and high photocatalytic activity.