Mesoporous I-Ag codoped titania and alumina modified titania catalysts: Synthesis, characterization and photocatalytic properties

Mesoporous iodine and silver codoped titania and alumina modified titania photocatalysts were synthesized by a two-step surfactant-templated hydrothermal route and characterized by X-ray diffraction, XPS, UV–visible diffuse reflectance spectroscopy and nitrogen adsorption. The mesoporous materials had surface areas of 2.6–5.3 times that of Degussa P25. The I-Ag codoped mesoporous titania samples exhibited a bicrystalline framework of rutile and anatase with rutile fractions of 23% and 26%, respectively, whereas the alumina-containing I-Ag codoped materials yielded anatase as the only crystalline phase. The I-Ag codoped photocatalysts with Ag/Ti mole ratio of 1.6% and 2.0% showed catalytic activity 3.3 times and 12 times higher than Degussa P25 under halogen visible and visible light (>400 nm) in photodecomposing methyl orange, respectively. The high performance of I-Ag codoped titania and alumina modified titania photocatalysts under visible light is attributed to the combined effects of large surface area, lower band gap energies and mesoporous structure.

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► High surface area mesoporous I-Ag-TiO2 and I-Ag-TiO2-Al2O3 photocatalyts synthesized.
► I-Ag-TiO2 and I-Ag-TiO2-Al2O3 shifted UV–vis adsorption into the visible range.
► The presence of Ag facilitated the incorporation of I in the structure.
► Ag-I-TiO2 and Ag-I-TiO2-Al2O3 with visible light photocatalysis up to 12× P25.