Novel 3D@2D/2D HHSS@BiOBr/Znln2S4 S-scheme photocatalyst for efficient adsorption-photocatalytic-photosensitization synergistic degradation of organics

Constructing high-performance multifunctional visible-light-driven photocatalysts to remediate organic contaminants from wastewater is of great challenge. Herein, we report a novel 3D@2D/2D hierarchical heterogeneous structured HHSS@BiOBr/Znln2S4 (HBZ) with abundant sulfur vacancies nanocomposite. This unique photocatalyst was fabricated by in situ growth of BiOBr nanosheets on the surface of hierarchical hollow silica spheres (HHSS), followed by epitaxial growth of Znln2S4 nanosheets for effective degradation of TCH and RhB. The optimal sample HBZ-6 (60 wt% Znln2S4) exhibited adsorption-photocatalytic synergistic degradation rate up to 92.36% after 30 min visible light irradiation, which was 2.31 times higher than that of bare BiOBr. It is benefit from the strong adsorption capacity of HHSS and effective carrier separation of 2D/2D S-scheme BiOBr/Znln2S4 in the HBZ-6 photocatalyst. Furthermore, it was surprising to discover that the coloured dye RhB was 100% photodegraded by HBZ-6 photocatalyst in 2 min under visible light, which is much faster than that of TCH with low visible light absorption. This excellent degradation efficiency is attributed to adsorption-photocatalyticphotosensitization synergistic between RhB and HBZ-6, leading to the ultrafast dye-sensitized-assisted electron transfer process. This work provides progressive tactics to design 3D@2D/2D defect heterogeneous structures which can greatly promote the future development of catalytic systems for wider application.