Optimizing catalytic performance of Ag2O/Na0.5Bi0.5TiO3 heterojunction by the piezo-phototronic coupling effect

The constructing of heterojunction piezo-photocatalysts has been regarded as a promising strategy in environmental remediation. Herein, a novel Ag₂O/Na_0.5Bi_0.5TiO₃ (Ag₂O/NBT) p-n heterojunction is designed by using a facile method, inducing the remarkable enhancement of photocatalytic performance by piezoelectric effect under ultrasonic vibration. The Ag₂O/NBT heterojunction can degrade 99 % Rhodamine B (RhB) within 30 min when exposed to light irradiation and ultrasonic vibration simultaneously, with a high reaction rate constant of 0.140 min⁻¹, which is 4.5 times and 17.5 times that of individual photocatalysis (0.031 min⁻¹) and piezocatalysis (0.008 min⁻¹), respectively. Moreover, the Ag₂O/NBT heterojunction exhibits excellent stability and reusability after five cycles. The improved piezo-photocatalytic performance can be attributed to the formation of p-n heterojunction and the generation of built-in electric field, which makes a high separation of photogenerated carriers. Finally, a possible piezo-photocatalytic mechanism for removal RhB was proposed based on the radical trapping experiment. It is expected that the results can provide valuable information for the further investigations of Ag₂O/NBT heterojunction as a potential piezo-photocatalyst in the environmental remediation.