Gas-phase photocatalytic decomposition of ethylbenzene over perlite granules coated with indium doped TiO2

Doped indium–TiO2 mesoporous photocatalysts were synthesized by a controlled sol–gel process. The catalysts were characterized by XRD, N2 physisorption, UV–Vis-DRS, Photoluminescence and Raman spectroscopies. The indium–TiO2 semiconductors were immobilized on perlite granules by a simple coating method and examined by SEM-EDS. Photocatalytic activity of the In–TiO2/perlite materials was evaluated by the decomposition of ethylbenzene in moist air in a plug-flow photoreactor with a concentric cylindrical configuration, under 254 or 365 nm irradiation. Ethylbenzene was substantially decomposed by oxidation in an air steam flowing over the In-doped coated/perlite granules. The decomposition rate of ethylbenzene may be attributed to the presence of indium, which can increase surface phenomena and sensitize the response of the semiconductors to the 365 nm UV irradiation. The materials with indium content show enhanced decomposition rates in contrast to the undoped materials. The study indicates that the immobilized In–TiO2/perlite photocatalysts may be a practical way to decompose volatile organic compounds in a stream of moist gas.

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► The In–TiO2 was coated on silicate granules for gas-phase ethylbenzene degradation.
► Plug-flow reactor packed with In–TiO2/granules was used to evaluate the degradation.
► In–TiO2 coated/granules show an enhanced decomposition rate of ethylbenzene.
► Photodecomposition rate of ethylbenzene strongly depends on the % of In2O3 into TiO2.
► In2O3–TiO2/perlite composites may be a practical way to decompose VOCs in moist gas.