CuO/NaNbO3 nanorod piezoelectric photocatalysts promoted tetracycline removal: a dynamic internal electric field

Abstract

Internal electric fields have been introduced into photocatalysts to separate photoinduced electrons and holes and improve photocatalytic efficiency. However, free carriers can quickly saturate a static internal electric field because of electrostatic shielding effect, which would suppress photoinduced carrier separation. Herein, CuO/NaNbO₃ (CNNO) nanorod piezo-photocatalysts were synthesized by introducing CuO nanoparticles on NaNbO₃ (NNO) nanorods. Under periodic ultrasound, a polarization potential would generate in NNO nanorods, acting as a dynamic internal electric field to sustainably separate photoinduced carriers. The piezoelectric effect of the as-prepared CNNO was demonstrated by piezo-response force microscopy (PFM). Photocurrent density tests indicated that the piezoelectric internal electric field could enhance the photocurrent response of CNNO. Furthermore, tetracycline (TC) degradation experiments were conducted under ultrasound and visible light irradiation to evaluate the photocatalytic performance of CNNO. Significantly, the photocatalytic elimination rate of TC by CNNO increased by 20% after the assistance of an internal electric field. This work achieved a coupling between the internal electric field and photocatalysis in CNNO, which could be a potential method to achieve efficient photocatalysis.