Construction of novel Z-scheme Ag/ZnFe2O4/Ag/BiTa1-xVxO4 system with enhanced electron transfer capacity for visible light photocatalytic degradation of sulfanilamide

Abstract

A novel Z-scheme system, Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ with enhanced electron transfer capacity was constructed for degrading sulfanilamide (SAM) using solar light. The photocatalytic activity of Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ was investigated. The effects of the mass ratio (ZnFe₂O₄:BiTaO₄), doped V dose, Ag wt.% content, and irradiation time on the catalytic performance were evaluated. The reasonable mechanism of Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ solar photocatalytic degradation was also presented. These results reveal Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ possesses enhanced photocatalytic performance. The loaded Ag as electron mediator increases the electron transfer rate. Particularly, the doped V and the Fe ions from ZnFe₂O₄ form a powerful electron driving force, which enhances the electron transfer capacity. Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ shows optimal photocatalytic performance at 2.0 wt.% Ag and 0.5% doped V dose (ZnFe₂O₄:BiTaO₄ = 1.0:0.5). Also, Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ exhibits high stability and repeatability in photocatalytic degradation. Several active species (^•OH, ^•O₂^-, and h⁺) are produced in the Z-scheme photodegradation of SAM. These results on the enhanced photocatalytic activity of Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ are ascribed to synergistic photocatalytic effects of ZnFe₂O₄ and BiTa_1-xV_xO₄ mediated through Ag and driven by doped V and Fe ions. Therefore, the Z-scheme Ag/ZnFe₂O₄/Ag/BiTa_1-xV_xO₄ photocatalytic technology proves to be promising for the solar photocatalytic treatment of antibiotics under solar light.

Keywords: Ag/ZnFe(2)O(4)/Ag/BiTa(1-x)V(x)O(4); Electron transfer capacity; Photocatalytic; Sulfanilamide; Visible light.