Tri-phase interface to enhance the performance of piezoelectric photocatalysis and recyclability of hydrophobic BiOI/BaTiO3 heterojunction

Piezo-photocatalysts exhibit remarkable efficacy in water pollutant treatment due to their efficient electron separation characteristics, while the interior recyclability and potentials for secondary pollution still limit the widespread application. In this study, a hydrophobically modified BiOI/BaTiO3 heterostructure was constructed, which demonstrated exceptional piezo-photocatalytic performance in RhB degradation (nearly 100 % within 30min) under irradiation and ultrasound. The kinetic rate constant (k) was 1.7, 2.1 and 24.1 times higher than BiOI/BaTiO3 without hydrophobically modifying, pure BiOI and BaTiO3, respectively. At the same time, the hydrophobically modified BiOI/BaTiO3 also has excellent degradation performance for other pollutants such as MB and SMX, which can degrade MB of 96.1 % and SMX of 82.3 % respectively within 30min. Additionally, HBBT exhibits exceptional recyclability (over 90 wt% after one cycle) and a low risk for secondary pollution due to the hydrophobicity-induced floating effect. Furthermore, the enhancing mechanism of piezoelectricity synergistic photocatalysis by the built-in electric field and tri-phase catalysis of air-liquid-solid joint interface for RhB degradation was explored and ascertained. This study may provide new ideas for efficient and highly recyclable photocatalytic water pollutant materials from the perspective of interface engineering. [Display omitted] •Hydrophobic BiOI/BaTiO3 exhibited tri-phase catalysis and piezo-photocatalysis.•Exceptional recyclability and a low risk for secondary pollution were proved.•A tri-phase piezo-photocatalytic mechanism for RhB degradation was proposed.