Effects of Al doping on properties of xAl–3%In–TiO2 photocatalyst prepared by a sol–gel method

A sol–gel method was used to prepare Al–In co-doped TiO2 photocatalyst. The materials were characterized by XRD, FT–IR, XPS, and N2 adsorption–desorption measurements. Photocatalytic degradation of methyl orange on the materials was investigated. The diffraction peaks of all the samples are in accordance to the diffraction peaks of anatase phase TiO2. The addition of Al and In can lead to crystallite size shrinking of anatase TiO2 in xAl–3%In–TiO2. The incorporation of Al3+ ions into TiO2 crystal are in the way of substituting Ti4+ ions in anatase lattice. 0.5%Al–3%In–TiO2 has the maximum specific surface area of 108.9 m2/g and the smallest average pore size of 7.0 nm. The aluminum doped xAl–3%In–TiO2 materials have larger adsorption capacity than that of 3%In–TiO2. Total decoloration efficiency increases gradually with increasing Al content up to 0.5%, while 0.5%Al–3%In–TiO2 has the maximal decoloration efficiency. 0.5%Al–3%In–TiO2 also shows much improved activity as compared to 3%In–TiO2 in each reuse cycle.