Z-scheme BiVO(4)/Ag/Ag(2)S composites with enhanced photocatalytic efficiency under visible light

The Z-scheme BiVO(4)/Ag/Ag(2)S photocatalyst was fabricated via a two-step route. The as-prepared samples were characterized by XRD, FE-SEM, HRTEM, XPS and UV-vis diffuse reflectance spectroscopy. The results of PL and photocurrent response tests demonstrate that the ternary BiVO(4)/Ag/Ag(2)S composites had a high separation and migration efficiency of photoexcited carriers. As a result, the ternary photocatalyst exhibits enhanced photocatalytic activity for decomposing Rhodamine B (RhB) under LED light (420 nm) irradiation. The results of trapping experiments demonstrate both h(+) and ˙OH play crucial roles in decomposing RhB molecules. Additionally, the energy band structures and density of states (DOS) of BiVO(4) and Ag(2)S were investigated via the density functional theory (DFT) method. Finally, a Z-scheme electron migration mechanism of BiVO(4) → Ag → Ag(2)S was proposed based on the experimental and calculated results.