Effects of surfactants on microstructure and photocatalytic activity of TiO2 nanoparticles prepared by the hydrothermal method

TiO2 nanoparticles were prepared using a surfactant (linoletic acid (LA) or polyethylene glycol-400 (PEG-400)) at various hydrolysis ratios (R=H2O/C2H5OH) by the hydrothermal method and studied for photocatalytic degradation of rhodamine B (RhB) under visible light irradiation. Special shapes of TiO2 nanoparticles, such as cubic, hexagon, bipyramid, and bullet, were found from the use of PEG-400 during the preparation. The cause for the formation of these special shapes is also discussed here. Interestingly, the hydrolysis ratios affected the Brunauer–Emmett–Teller (BET) special surface areas of the TiO2 nanoparticles. Owing to the effects of the surfactant PEG-400 on the microstructures, the resulting materials exhibited relatively higher photocatalytic activity than conventional TiO2 nanoparticles in the presence of LA. Furthermore, P-TiO2-8/10 (P is PEG-400 and 8/10 is H2O/C2H5OH molar ratio) nanoparticles had a similar photocatalytic activity to P25 and TiO2-10/10.