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Different semiconductive SiC foam supports were prepared by varying the sintering temperature and atmosphere,and with or without alkaline solution treatment and high temperature oxidation following a macromolecule pyrogenation combined with reaction bonding method.Nano-TiO_2 particles were immobilized onto these SiC foam supports by a composite sol—gel method.The phase,surface morphology,the type of conduction and the photocatalytic activity of the TiO_2—SiC composite photocatalysts were studied.The TiO_2coated on p-type Si-free SiC support showed the highest photocatalytic efficiency in degradation of 4-aminobenzenesulfonic acid(4-ABS) in aqueous solution as compared to that coated on n-type SiC support and p-type SiC supports with residual Si or SiO_2 on the surface.The result showed that the TiO_2 coatings immobilized on p-type semiconductive SiC foam supports exhibited obviously higher photocatalytic activity in comparison to that coated on n-type SiC foam support.The p—n heterojunctions formed between the p-type SiC supports and n-type TiO_2 coatings might be able to account for the better charge separation and transfer as well as the photocatalytic activity of the TiO_2—SiC composite photocatalyst.
Different semiconductive SiC foam supports were prepared by varying the sintering temperature and atmosphere, and with or without alkaline solution treatment and high temperature oxidation following a macromolecule pyrogenation combined with reaction bonding method. Nano-TiO_2 particles were immobilized onto these SiC foam supports by a composite sol-gel method. The phase, surface morphology, the type of conduction and the photocatalytic activity of the TiO 2 -SIC composite photocatalysts were studied. TiO 2 coated on p-type Si-free SiC support showed the highest photocatalytic efficiency in degradation of 4- aminobenzenesulfonic acid (4-ABS) in aqueous solution as compared to that coated on n-type SiC support and p-type SiC supports with residual Si or SiO 2 on the surface. The result showed that the TiO 2 coatings immobilized on p-type semiconductive SiC foam supporthips obviously higher photocatalytic activity in comparison to that coated on n-type SiC foam support.The p-n het erojunctions form between the p-type SiC supports and n-type TiO 2 coatings might be able to account for the better charge separation and transfer as well as the photocatalytic activity of the TiO 2 -SiC composite photocatalyst.