Controllable synthesis of multi-responsive ferroelectric layered perovskite-like Bi4Ti3O12: Photocatalysis and piezoelectric-catalysis and mechanism insight

Development of multi-responsive catalytic materials is a highly meaningful and challenging subject for forwarding the understanding on catalysis mechanism. In this work, we for the first time disclose the piezoelectric-catalytic performance and morphology-dependent photocatalytic activity of Bi4Ti3O12. Via introducing and manipulating the mineralizer sodium hydroxide, we developed a series of Bi4Ti3O12 catalysts with diverse morphologies, including nanorods, slice-assembled microspheres, nest-like hollow microspheres, and cube assembly. The photocatalytic activity of these hydrothermally-yielded Bi4Ti3O12 as well as sol-gel derived Bi4Ti3O12 is investigated by degradation of phenol, and the photocatalytic mechanism is explored. The Bi4Ti3O12 microsphere exhibits the most efficient degradation activity, and also presents universal photoreactivity for removing multiform contaminants and antibiotics, like bisphenol A, rhodamine B, chlorotetracycline and tetracycline hydrochloride, boding for its promising practical applications. Significantly, Bi4Ti3O12 demonstrates a high piezoelectric-catalytic performance for ultrasonic-assisted decomposition of methyl orange, bisphenol A and tetracycline hydrochloride. It is uncovered that both powerful superoxide (O-center dot(2)-) and hydroxyl ((OH)-O-center dot) radicals are generated with production rates of 6.4 and 2.4 mu mol g(-1) h(-1), respectively, which take crucial roles in the piezoelectric-catalytic process. The corresponding mechanism is tentatively speculated. This work may push forward to the development of multi-responsive catalytic materials, and provide insights into piezoelectric-catalysis for environmental applications. (C) 2017 Elsevier B.V. All rights reserved.