Design of magnetically separable double Z-scheme Ag3PO4/Fe3O4/MoS2 heterojunction with enhanced photocatalytic degradation of antibiotics under visible light irradiation

Photocatalysis is a promising technology in treating antibiotic wastewater. However, the rapid recombination of photogenerated electron-hole pairs and the loss of photocatalysts make its practical application challenging. To address these issues, a double Z-scheme heterojunction of magnetically separable Ag3PO4/Fe3O4/MoS2 photocatalyst is designed and applied for the photocatalytic degradation of tetracycline hydrochloride (TCH). The degradation efficiency of TCH by Ag3PO4/Fe3O4/MoS2 can achieve 99.0 % within 7.5 min under visible light irradiation, which is still above 91.3 % after 7 cycles. The excellent photocatalytic performance is attributed to the enhanced carrier life by constructing the double Z-scheme heterostructure in Ag3PO4/Fe3O4/MoS2. Mechanistic study indicates that center dot O-2(-), center dot OH, and h(+) radicals are generated during the photocatalytic degradation. Combining experimental and theoretical calculations, two main degradation pathways are proposed, and the toxicity of the degradation system is significantly reduced. This study provides fresh insights into the photocatalytic degradation of refractory antibiotics by constructing magnetically separable Ag3PO4/Fe3O4/MoS2 heterojunction.