Excellent piezo-photocatalytic performance of Bi4Ti3O12 nanoplates synthesized by molten-salt method

Bi 4 Ti 3 O 12 is one of the Aurivillius-type layered perovskite oxides with superior photocatalytic effect, however, the further enhancement of this effect is limited by the high recombination rate of photo-generated carriers. Here, piezo-phototronic effect was employed to significantly improve the photocatalytic performance of Bi 4 Ti 3 O 12 nanoplates synthesized by molten-salt method. Under light and ultrasonic excitations, the screening effect of the built-in electric field caused by ferroelectric polarization can be broken by the alternating piezoelectric potential due to the periodic mechanical stress, and thus the reaction rate k of piezo-photocatalytic degradation of RhB reaches 0.1414 min −1 which is 5.6 times of piezocatalytic k value and 2.1 times of photocatalytic k value. This k value is much larger than that of Bi 4 Ti 3 O 12 nanoplates and Bi 4 Ti 3 O 12 nanoflowers synthesized by solid-state reaction method and hydrothermal method, respectively. Due to the good balance of size, shape, crystallinity and specific surface area, Bi 4 Ti 3 O 12 nanoplates synthesized by molten-salt method exhibit better piezo-photocatalytic performance for degrading RhB. This work is helpful to develop other efficient piezo-photocatalysts. • The monodisperse and highly crystalline Bi 4 Ti 3 O 12 nanoplates were synthesized by one-step molten-salt method. • Photocatalytic performance was significantly improved through piezotronic effect. • The reaction rate of piezo-photocatalytic degradation of RhB reaches 0.1414 min −1 .