Microwave and Conventional Hydrothermal Synthesis of TiO2 Nanoparticles and their Photocatalytic Activities

Abstract

Series of anatase TiO2 nanoparticles with different particle sizes were prepared by a fast microwave-assisted method and conventional hydrothermal method, using ionic liquids, 1-ethyl-2,3-dimethylimidazole bromide and N-butylpyridinium hexafluorophosphate, and polyethylene glycol as templates, respectively. The crystal structures and morphologies of the nanoparticles were characterized by XRD and SEM. Their light harvesting capabilities and band gap energies were investigated by UV-Vis diffuse reflectance absorption spectra. The surface –OH groups were detected by FT-IR and the photocatalytic activities were estimated by photodegradations of rhodamine B aqueous solutions under simulated sunlight irradiation. The results show that the type of the template and synthetic method affect the particle sizes of the products, and the photocatalytic activities of the TiO2 nanoparticles are close related with their particle sizes.