Synthesis and Characterization of Z-Scheme Ag/AgI/Bi2WO6 Photocatalyst for Enhanced Rhodamine B Degradation under Visible Light

Abstract

Z-scheme Ag/AgI/Bi2WO6 nanocomposites as visible-light-driven photocatalysts have been successfully prepared by precipitation–sonochemical deposition method. Structure, morphology, composition and optical property of as-prepared Z-scheme Ag/AgI/Bi2WO6 nanocomposites have been characterized by X-ray powder diffraction, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The Z-scheme Ag/AgI/Bi2WO6 photocatalysts have been composed of a major phase of orthorhombic Bi2WO6 and two minor phases of face centered cubic AgI and face centered cubic metallic Ag. These nanocomposites show fully AgI and Ag/AgI nanoparticles supported on top of Bi2WO6 nanoplates. The Z-scheme Ag/AgI/Bi2WO6 photocatalysts have photocatalytic activity for the degradation of rhodamine B (RhB) higher than pure Bi2WO6 sample and AgI/Bi2WO6 nanocomposites under visible radiation because of the synergistic effect of heterojunctions containing in the Ag/AgI/Bi2WO6 nanocomposites and surface plasmon resonance effect of Ag nanoparticles. The trapping experiment proved that h+ and $$^{\bullet }{\text{O}}_{2}^{ - }$$ have the major roles in degrading RhB over Ag/AgI/Bi2WO6 nanocomposites induced by visible radiation.