Study the photocatalytic mechanism of the novel Ag/p-Ag2O/n-BiVO4 plasmonic photocatalyst for the simultaneous removal of BPA and chromium(VI)

Abstract

Herein, we demonstrate the successful construction of a novel flowerlike Ag/p-Ag2O/n-BiVO4 plasmonic photocatalyst for the photocatalytic oxidation of BPA and reduction of chromium(VI) simultaneously under visible light irradiation. Among these samples, 2mM-Ag/p-Ag2O/n-BiVO4 exhibits the highest photocatalytic performances. The photocatalytic reduction and oxidation efficiency can achieve 69.8 and 91.9%, respectively, after 100 min visible-light irradiation. The enhancement mechanism for the plasmonic photocatalyst is explored, which can be attributed to the enhanced absorbance in the visible light region, and the facilitated charge transfer and the suppressed recombination of electron-hole pairs in the Ag/p-Ag2O/n-BiVO4. The results of the electrochemical impedance spectroscopy, the fluorescence emission spectra and the time-resolved fluorescence emission decay spectra indicate the enhanced charge separation in the Ag/p-Ag2O/n-BiVO4 plasmonic photocatalyst. In addition, the free radical scavenging test shows that h+ and OH radicals play crucial roles in the photocatalytic oxidation reaction. The photogenerated electrons in the photocatalytic reduction process, are confirmed by the DMPO spin-trapping technology. Moreover, the band structures of various photocatalysts are revealed via the valence band XPS spectra and the Fermi level obtained by CASTEP code.