Synthesis of Mesoporous Anatase TiO2 Sphere with High Surface Area and Enhanced Photocatalytic Activity

Abstract

Mesoporous anatase TiO 2 spheres with high surface area (119 m 2 g −1 ) were successfully synthesized via a facile and green template-free method. The prepared TiO 2 was characterized by X-ray diffraction (XRD), N 2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis absorbance spectra. It was found that the prepared TiO 2 is characterized by pure anatase phase, which shows uniform spheres and has a typical mesostructure with a high specific surface area and a large pore volume. The effects of complexant (acetylacetone) amount, crystallization temperature and calcination temperature were also investigated. Based on the results, a sketch for the preparation of mesoporous TiO 2 was proposed. First, complex formed between tetrabutyl titanate and acetylacetone in ethanol. After introduction of aqueous of ammonia sulfate and urea, hydrolysis of tetrabutyl titanate would occur slowly, and sol of TiO 2 was formed. Then, crystallization proceeded under hydrothermal conditions. Calcination process favored the formation of bigger TiO 2 crystal through combining of the small crystals in TiO 2 . This led to the formation of bigger mesopores between TiO 2 crystals. Photocatalytic activity of the prepared TiO 2 was evaluated by decomposition of methyl orange.