Low-frequency porous composite foam catalyst for efficient dye wastewater degradation via coupling photoelectric and piezoelectric effects

Abstract

Privileged photocatalysts combine semiconductor physics, materials science, chemical engineering and environmental science to convert abundant photonic energy into chemical energy. A common limitation of photocatalysts at-scale processes is their insufficient light absorption capability and charge carrier management. Additionally, the potential secondary pollution and difficulties in effective recovery associated with the dispersion of traditional powder catalysts in the water further limit their industrial application. To address these issues, strong electric fields generated by the piezoelectric effect were introduced to reduce the scattering probability of photoinduced carriers during their migration, thereby significantly enhancing photocatalytic efficiency. Specifically, we have developed a PDMS-loaded solid solution 0.7 BiFeO3-0.3 BaTiO3 (BFBT) hybrid catalyst that achieves a degradation rate of 99% for Rhodamine B solution within 60 min under the synergistic action of low-frequency vibration and light irradiation. The degradation kinetic constant was 0.080 min−1, representing a piezoelectric enhancement of photocatalysis by 148%. The internal electric field is excited by periodic mechanical stress, which finely regulates the interface energy band structure, promotes the effective separation of photoinduced carriers and enhances the generation of reactive oxygen species, thereby strengthening the chemical reaction kinetics and achieving efficient degradation of pollutants.