Synergistic catalysis of BiOIO3 catalyst for elimination of organic pollutants under simultaneous photo-irradiation and ultrasound-vibration treatment

Abstract Development of efficiently catalytic strategy for oxidative purification of organic pollutants is of great significance. Photocatalysis has become one of the most important technologies in the past half a century, but the inefficiency of photocatalysts drastically suppresses its practical application. This work proposes a synergistic photopiezocatalysis of BiOIO3 under simultaneous photo-irradiation and ultrasound-vibration treatment to degrade various organic pollutants. Different from the high recombination of photo-excited charges in photocatalysis, the ultrasound-induced stress deforms the pyroelectric BiOIO3 to form a piezoelectric potential that drives photo-/thermo-generated free electrons and holes in catalyst to diffuse along opposite directions. In comparison with the single photocatalysis and piezocatalysis, the photopiezocatalysis possesses a synergistic effect, presenting evidently enhanced catalytic performance for decomposing a variety of organic dyes and a persistent organic pollutant 2,4-DCP. No apparent decrease in activity during successive five runs demonstrates that the photopiezocatalysis of BiOIO3 has a high stability and reusability. Finally, a plausible photopiezocatalysis mechanism is proposed based on the determination of active species produced on catalyst and intermediates during pollutant degradation. Our findings provide a new insight to promote charge separation and meanwhile develop an efficient synergistic photopiezocatalysis for environment remediation.