Effective visible-light excited charge separation in all-solid-state Ag bridged BiVO4/ZnIn2S4 core-shell structure Z-scheme nanocomposites for boosting photocatalytic organics degradation

Abstract Designing and fabricating high-powered Z-scheme photocatalysts are highly desired to improve the visible-light activity for efficiently degrading organic pollutants. In this work, a novel all-solid-state Ag bridged BiVO4/ZnIn2S4 (BiVO4/Ag/ZnIn2S4) core-shell structure Z-scheme nanocomposite is constructed by multi-step solvothermal method with in-situ growth, in which the degradation rate of 2,4-DCP is 4 times than that of BiVO4 within 3 h. On the basis of Valence Band-X-ray photoelectron spectroscopy (VB-XPS) spectra, Kelvin probe force microscopy, single-wavelength photoactivities and DMPO spin-trapping electron paramagnetic resonance (EPR) spectra, the exceptional photoactivities of BiVO4/ZnIn2S4 core-shell structure is mainly attributed to the Z-scheme mechanism of BiVO4/ZnIn2S4 exhibits significant effect on the promotion of photogenerated charge separation within the system. Excitingly, it has been proved that the photogenerated charge of Z-scheme mechanism can be further effectively separated by introducing Ag bridges between BiVO4 and ZnIn2S4, as supported by photophysical, photochemical and photoelectrochemical tests. In practice, this work provides valuable experience for develop new core-shell structure BiVO4-based narrow band gap photocatalysts for organic degradation. In theory, it further reveals the photogenerated transfer mechanism and improvement paths in the Z-scheme system.