Achieving remarkable piezo-photocatalytic activity in Sr2Bi4Ti5O18/BiOCl sandwich ferroelectric heterojunction with continuous semi-coherent interfaces via selective etching of Aurivillius perovskite solid

Constructing ferroelectric hetrojuction and utilizing its piezo-photocatalytic performances is a promising approach for environmental remediation and sustainable energy conversion. However, challenges such as electron-hole recombination and interfacial instability limit the performance of piezoelectric heterojunction photocatalysts. In this study, a novel sandwich-structured heterojunction with a lattice-matched interface constructed by Sr 2 Bi 4 Ti 5 O 18 (SBTO) bismuth Aurivillius phase ferroelectric material and BiOCl (BOC) was developed via a selective etching strategy. This approach minimizes interfacial defects and stress, while ferroelectric polarization modulates charge distribution, enhancing redox activity. Finite element simulations and experimental results demonstrate that the SBTO/BOC heterojunction leverages intrinsic and interfacial electric fields to form dual electron transport pathways, significantly improving charge separation in both bulk and interface regions. The optimized SBTO/BOC heterojunction achieves a piezo-photocatalytic degradation rate of 0.285 min −1 for Rhodamine B, approximately twice that of Sr 2 Bi 4 Ti 5 O 18 under piezo-photocatalysis (0.147 min −1 ) and 13 times higher than photocatalysis alone (0.022 min −1 ). The heterostructure also efficiently degrades dyes, antibiotics, and Cr(VI), offering a robust design for high-performance piezo-photocatalytic systems.