Crystal face-selective Bi4Ti3O12/BiOI heterojunction constructed for enhanced visible ligtht-driven photocatalytic activity

[Display omitted] •Crystal face-selective Bi4Ti3O12/BiOI heterojunction was synthesized by epitaxy growth.•Bi4Ti3O12/BiOI-3 heterojunction exhibits the best photocatalytic activity for degrading RhB solution among all samples.•Ferroelectric properties show vital influence for photocatalytic activity.•The mechanism of enhanced photocatalytic activity was discussed. Spontaneous polarization of ferroelectric is used to promote the separation of photogenerated electrons and holes, showing tremendous potentials of solar-light driven photocatalytic. However, designing a system of efficient response to visible light, remains a fundamental challenge due to rapid recombination of electrons-holes and weak absorption in visible region. Here, we synthetized Bi4Ti3O12/BiOI heterojunction, which BiOI nanosheets selectively deposited on (110) facets of Bi4Ti3O12 by epitaxy growth. The synthetized heterojunction is characterized by phase structures, morphology, and surface chemical state. The results of ferroelectric phase curve illustrate that the construction of heterojunction enhances the ferroelectric properties, which is favorable to improve the separation and recombination processes of carriers. Furthermore, the sample Bi4Ti3O12/BiOI-3 reveals better photocatalytic kinetics in photodegradation of bisphenol A (BPA) under visible-light irradiation, which is about 74.16 and 1.83 times faster than that of pure Bi4Ti3O12 and BiOI. This work provides an effective and scalable strategy for designing a system of efficient response to visible light.