Preparation, characterization and activity evaluation of heterojunction ZrTi2O6/TiO2 photocatalyst

A new heterojunction photocatalyst ZrTi2O6/TiO2 was synthesized by a sol-gel method using ZrOCl2·8H2O and tetrabutyl titanate [Ti(OC4H9)4] as the raw materials. The structure and optical properties of the ZrTi2O6/TiO2 photocatalyst were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), and UV-Vis diffuse reflection spectrum (DRS). The photocatalytic activity of the photocatalyst was evaluated by photocatalytic reduction of Cr2O72− and photocatalytic oxidation of methyl orange (MO). The production of hydroxyl radicals (OH) during the photocatalytic process was detected by a photoluminescence (PL) technique using terephthalic acid as a probe molecule. The results showed that photocatalytic activity of the ZrTi2O6/TiO2 photocatalyst (mole ratio of Zr/Ti is 1:1, heat treatment at 600 °C for 2 h) was higher than that of other samples and pure-TiO2. The heterojunction between ZrTi2O6 and TiO2 was confirmed by HR-TEM. And the mechanism of the increased photocatalytic activity was also discussed.