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.