Structure characteristics and photocatalytic performance of black TiO₂/MMT with Ti-O-Si bond

As an interesting photocatalytic material, black TiO2 has high research and application value. Some desirable adsorption and photocatalytic composites will be fabricated in combination black TiO2 with montmorillonite (MMT). In this paper, nano-structures of TiO2/MMTs were characterized by XRD, FT-IR, Raman, XPS, PL and UV-Vis DRS. It can be concluded that the existence of MMT delays the crystal transformation of TiO2. New Ti-O-Si bonds, oxygen vacancy clustering and minimal Ti (III) contents were emerged and intensified in black TiO2/MMT. These special structures are helpful to preventing the recombination of electrons and holes which were used to degrade the dye molecules. The photocatalytic performance was determined by the decolorization ratio of two kinds of dyes under sunlight or indoor visible light. The degradation efficiencies of rhodamine B (Rh B) and methyl orange (MO) can reach 78.7% and 53.2%, respectively, after illuminated for 140 min under sunlight. The assessment of radical scavengers shows that the main functional radicals in the degradation of Rh B and MO were O-2- and OH, respectively. These new catalysts have wide range of utilization in the degradation of phenols, aromatics, pesticides and antibiotics compounds.