Rapid microwave-assisted sol-gel synthesis and exceptional visible light photocatalytic activities of Bi12TiO20

Crystalline Bi12TiO20 and Bi4Ti3O12 particles were selectively synthesized by rapid microwave-assisted sol-gel method. During the thermal decomposition process of the dried gel, microwave calcination played a key role in producing single phase Bi12TiO20. Our Bi12TiO20 demonstrated one of the highest visible-light photocatalytic activities for MO degradation among the reported bismuth titanate particles with various compositions. Single phase Bi4Ti3O12 can also be prepared by either a conventional calcination at high temperature or a combined heat treatment of a conventional heating followed by microwave calcination. The photocatalytic reaction rate constant of the Bi4Ti3O12 prepared by microwave calcination was three times higher than that of conventionally calcined Bi4Ti3O12, further confirming the advantage of microwave calcination in preparation of highly photocatalytically active bismuth titanate.