Morphology and photocatalysis of mesoporous titania thin films annealed in different atmosphere for degradation of methyl orange

The effect of different annealing atmosphere on the morphology and photocatalytic activity of mesoporous TiO₂ thin films by dip-coating technique is investigated. The annealing temperature and atmosphere causes significant change of the morphology, thermal stability, photoluminescence, and photocatalytic properties of mesoporous TiO₂ films. As-prepared mesoporous thin films have an amorphous structure that is transformed to crystalline TiO₂ with well-maintained mesoporous structure at 450°C in various annealing atmosphere except that the mesoporous structure is fully destroyed for films annealed in air. Films annealed in N₂ show the enhanced UV photodegradation of methyl orange (MO) resulting from the enhanced crystallinity in these films evidenced by XRD and Raman spectra. These findings can be used to tailor the structure and morphology of mesoporous TiO₂ films and thus improve their photocatalytic activity for efficient removal of dye effluents in wastewater.