Preparation and Characterization of Visible-light Irradiated TiO₂/Bi₄Ti₃O₁₂ Composite Powder

With micro-sized Bi4Ti3O12 platelet prepared by molten salt method as the substrate, the TiO2/ Bi4Ti3O12 composite powders were prepared by the hydrolysis of titanium sulfate followed by heat treatment. The effects of raw material ratios on the crystal structure, morphology and photocatalytic degradation/decolorization performance of the composite powders were investigated. The results show that the composite powders showed the morphology of nano-scale TiO2 particles distributing on the surface of micro-scale Bi4Ti3O12 platelets. When the molar ratio of Bi/Ti in raw materials was lower than 1∶6, the adsorption decolorization effect of the composite powder on methylene blue was good. But a relatively high content of Ti could result in the agglomeration of the hydrolysis product and lowered the surface area of the composite powder, leading to the poor decolorization effect. When the molar ratio of Bi/Ti was equal to 1∶4, the BET surface area of the composite powder reached 13.444 m2·g-1, and the methylene blue decolorization rate reached 85% under visible light irradiation in 4 h. The photocatalytic degradation/decolorization rate was higher than that of pure Bi4Ti3O12.