Bi6Fe2Ti3O18 ferroelectrics with various morphologies under mild conditions by crystal growth control for promoted adsorption-piezo-photocatalytic degradation performances

Abstract

Bi6Fe2Ti3O18 (BFTO) Aurivillius phase layered perovskite ferroelectric materials with spontaneous polarization and piezoelectric effect, have garnered significant attention in photocatalysis owing to their unique advantage of enhancing electron-hole separation. Herein, morphological engineering is used to improve the photocatalytic, piezo-catalytic, and piezo-photocatalytic activities of BFTO, and BFTO nanocrystallites with diverse morphologies such as nanosheet, nanoparticle, nanosheets-assembled flower-like structures were successfully synthesized using a hydrothermal method under mild conditions. Among these structures, the flower-like BFTO sample exhibits efficient absorption of visible light, excellent adsorption performance, enhanced piezoelectric response, and effective carrier separation, thereby contributing to its superior adsorption-photocatalytic, adsorption-piezo-catalytic, and adsorption-piezo-photocatalytic activities for Rhodamine B. Furthermore, corona poling was further applied to enhance the macroscopic polarization and piezoelectric response of the BFTO photocatalyst, thereby leading to more effective separation of photogenerated carriers in the polarized samples. The polarized BFTO microflowers exhibit excellent photocatalytic, piezo-catalytic, and piezo-photocatalytic activities with reaction rate constants of 0.222 min−1, 0.168 min−1, and 0.255 min−1. Based on the results of piezoresponse force microscopy and finite element simulation, the greater piezoelectric response was confirmed in the polarized flower-like BFTO compared to the other samples. Overall, the synergistic effect of morphology control and polarization engineering is effective for achieving Bi-based Aurivillius phase layered perovskite photocatalyst with excellent adsorption-photocatalytic and adsorption-piezo-photocatalytic performances.