Preparation of SnO^sub 2^-TiO^sub 2^/Fly Ash Cenospheres and its Application in Phenol Degradation

SnO2-TiO2/fly ash cenospheres (FAC) were prepared via hydrothermal method and used as an active photocatalyst in a photocatalytic system. Scanning electron microscopy, X-ray diffraction analysis, UV-Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy and N2 adsorption-desorption measurements were used to determine the structure and optical property of SnO2-TiO2/FAC. Phenol was selected as the model substance for photocatalytic reactions to evaluate catalytic ability. Results showed that the degradation efficiency of phenol by SnO2-TiO2/FAC was 90.7% higher than that decomposed by TiO2/FAC. Increased efficiency could be due to the enhanced synergistic effect of semiconductors and FAC could provide more adsorption sites for the pollutant in the photocatalytic reaction. Furthermore, SnO2-TiO2/FAC composites exhibited excellent photocatalytic stability in four reuse cycles. Radical-trapping experiments further revealed the dominating functions of holes in the photocatalytic reaction.