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

A novel 3D@2D/2D hierarchical heterogeneous structure of HHSS@BiOBr/Znln2S4 with abundant sulfur vacancies composite photocatalysts based on unique porous hierarchical silica hollow spheres HHSS is beneficial in achieving adsorption-photocatalysis-photosensitisation (Tai Chi Eight Trigrams) synergistic effects to ultra-fast photodegradation of TCH and RhB, respectively. [Display omitted] •Constructing HBZ composite photocatalysts with 3D@2D/2D hierarchical heterogeneous structures.•The hierarchical heterogeneous structures improved the accessibility of sulfur active sites.•HBZ achieved adsorption-photocatalysis synergistic degradation of TCH.•Ultra-fast photodegradation of RhB by co-operative adsorption-photocatalysis- photosensitization.•Possible mechanisms for photodegradation of RhB and S-scheme dye-sensitized-assisted electron transfer processes were proposed. 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-photocatalytic-photosensitization 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.