Synthesis and enhanced piezophotocatalytic activity of Ag2O/K0.5Na0.5NbO3 composites

Ag2O/K0.5Na0.5NbO3 (Ag2O/KNN) piezophotocatalysts with different weight ratios of Ag2O to KNN were synthesized by a facile two-step method involving hydrothermal and precipitation methods. Ag2O particles were attached on the surface of KNN via a precipitation method. Ag2O/KNN composites exhibit better photoactivity than pure Ag2O and KNN under visible light irradiation. Moreover, under both irradiations of visible light and ultrasound, the piezophotocatalytic activity was further enhanced in comparison with photoactivity. Based on the experimental results, the improved piezophotocatalytic activities of Ag2O/KNN composites should be attributed to the formation of p-n heterojunction between Ag2O and KNN and the generation of external electric field of KNN, which leads to high separation rate of photo-induced charges. The photostability and corresponding piezophotocatalytic mechanism were discussed.