A novel stratagem for synthesis of S-scheme Ag3PO4/ZnO nanocomposites by sol-gel assisted sonochemical route for removal of rhodamine B under visible light radiations

Abstract

In this research work, S-scheme Ag₃PO₄/ZnO heterojunctions were synthesized by sol-gel assisted sonochemical route for photocatalytic degradation of rhodamine B dye under visible radiations. ZnO nanoparticles were synthesized by controlled sol-gel route using pluronic as pore directing templating agent. Various concentration of Ag₃PO₄ [0–20] wt% were coupled with ZnO sonochemically for generating S-scheme Ag₃PO₄/ZnO heterojunctions with strong redox power in degrading RhB dye. The physicochemical properties of the as-synthesized samples were monitored by [XRD], N₂-adsorption-desorption isotherm, [HRTEM], [DRS], Mapping, [PL], [EDX] and [XPS] devices. HRTEM analysis implied the controlled distribution of spherical Ag₃PO₄ on localized active sites of ZnO surface. The experimental results implied that incorporating 15 wt% of Ag₃PO₄ on ZnO surface increased the surface area from 4 to 22 m²/g implying the production of more available active sites. The visible light absorbability of ZnO was greatly enhanced with incorporating various proportions of Ag₃PO₄ which ascribed to the narrow band gap energy of Ag₃PO₄ [2.4 eV]. The experimental results revealed that photocatalytic efficiency of the a-synthesized samples increased with introducing various proportions of Ag₃PO₄ on ZnO surface due to generation of S-scheme Ag₃PO₄/ZnO heterojunctions with superior charge carriers separation and transportation. Scavenger trapping experiments revealed that hydroxyl and superoxide radicals exhibited a crucial role in destructing RhB dye under light illumination. The novel S-scheme Ag₃PO₄/ZnO is considered a promising candidate for destructing organic pollutants in wastewater.

Graphical Abstract