Effect of hydrogen peroxide on the structure and photocatalytic activity of titania

Great attention has been paid to the fabrication of TiO2 hollow microspheres (TiO2-HMS) with enhanced photocatalytic activity due to the low density, high surface area, good surface permeability, and greater light-harvesting capacity. In this paper, TiO2-HMS were fabricated by a simple hydrothermal route in a Ti(SO4)(2)-H2O2 mixed solution at 180 A degrees C for 10 h. The prepared photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and nitrogen adsorption-desorption isotherms. The photocatalytic activity of the photocatalysts were evaluated by degradation of Brilliant Red X3B (X3B), an anionic dye, and the formation of the photo-induced hydroxyl radicals (center dot OH) under UV irradiation. The presence of hydrogen peroxide not only results in the formation of TiO2-HMS but also stimulates the phase transformation of TiO2 from anatase to rutile. The photocatalytic activity of the photocatalyst was found to first increase and then to decrease with the increase in the amount of H2O2. H2O2 can enhance the crystallization of anatase TiO2. However, too much H2O2 results in the formation of the rutile phase, which has a negative role on the photocatalytic activity of TiO2-HMS.