Preparation of SnO2 -TiO2 /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.