Piezoelectricity-enhanced photocatalytic degradation performance of SrBi4Ti4O15/Ag2O p-n heterojunction

Ferroelectric materials will generate an internal electric field when subjected to force, thus assisting to separate the photogenerated carriers. Here, a ferroelectric SrBi4Ti4O15/Ag2O p-n heterojunction catalyst is designed, inducing the remarkable enhancement of photocatalytic degradation performance by piezoelectric effect under the direct current electric field. The polarized SrBi4Ti4O15/Ag2O degrades 99.54 % Rhodamine B (RhB) within 6 min when exposed to light and ultrasonic vibration simultaneously, with an ultra-high degradation rate constant (k = 0.8949 min−1), which is 3.24 times of photocatalytic degradation rate (0.2765 min−1) and 17.38 times of the piezocatalytic degradation rate (0.0515 min−1). Moreover, SrBi4Ti4O15/Ag2O piezo-photocatalyst presents excellent degradation effect on methylene blue (MB), methyl violet (MV), methyl orange (MO) and tetracycline (TC). The piezoelectric effect induced by ultrasonic vibration provides a built-in electric field, which significantly enhances the separation of photoexcited carriers, consequently improving the photocatalytic degradation properties of SrBi4Ti4O15/Ag2O. This study provides a valuable reference for designing efficient photocatalysts by coupling photocatalysis and piezoelectric effect.