An effective strategy for boosting photoinduced charge separation of Ag3PO4 by BiVO4 with enhanced visible light photodegradation efficiency for levofloxacin and methylene blue

Abstract

In this paper, a Z-scheme Ag₃PO₄/BiVO₄ photocatalyst was successfully prepared by precipitation-deposition method. The Ag₃PO₄/BiVO₄ composite exhibited enhanced photocatalytic activity and recyclability for levofloxacin and methylene blue degradation under visible light irradiation. In the Ag₃PO₄/BiVO₄-0.4 system, up to 92.44% of the levofloxacin molecules can be decomposed within 180 min and the photocatalytic degradation efficiency can maintain at 92.02% for methylene blue after recycled for 5 times. The enhanced photocatalytic activity of Ag₃PO₄/BiVO₄ heterojunctions could be mainly attributed to the fabrication of hetero-structure between BiVO₄ and Ag₃PO₄. The photogenerated electron-hole pair separation was effectively enhanced based on the photocurrent, electro-chemical impedance spectra and photoluminescence data. Furthermore, the electrons transfer from photoinduced BiVO₄ to Ag₃PO₄ and the visible light harvesting efficiencies were significantly increased due to the BiVO₄ hybridization. The ·OH was the main oxidative species in the Ag₃PO₄/BiVO₄ system for the methylene blue decomposition. Finally, a purposed photocatalytic mechanism for methylene blue degradation was discussed in detail on the basis of experimental results.

Keywords: Heterojunction; Levofloxacin; Monoclinic scheelite (BiVO(4)); Silver phosphate (Ag(3)PO(4)).