Rapid microwave-assisted sol-gel synthesis and exceptional visible light photocatalytic activities of Bi 12 TiO 20

Abstract Crystalline Bi 12 TiO 20 and Bi 4 Ti 3 O 12 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 Bi 12 TiO 20 . Our Bi 12 TiO 20 demonstrated one of the highest visible-light photocatalytic activities for MO degradation among the reported bismuth titanate particles with various compositions. Single phase Bi 4 Ti 3 O 12 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 Bi 4 Ti 3 O 12 prepared by microwave calcination was three times higher than that of conventionally calcined Bi 4 Ti 3 O 12 , further confirming the advantage of microwave calcination in preparation of highly photocatalytically active bismuth titanate.