Fabrication of magnetically recoverable photocatalysts using g-C₃N₄ for effective separation of charge carriers through like-Z-scheme mechanism with Fe₃O₄ mediator

A novel efficient magnetic oxidation-reduction like-Z-scheme structure photocatalyst composed of g-C₃N₄, CdS and the oxidation-reduction mediators of Fe₃O₄ is successfully synthesized by heat treatment methods. The like-Z-scheme CdS/Fe₃O₄/g-C₃N₄ photocatalyst exhibits universal degradation property on removing kinds of antibiotics, and the photocatalytic activity is better than that of CdS/g-C₃N₄ and pure g-C₃N₄. The excellent photocatalytic performance is originated from the unique like-Z-scheme structure and oxidation–reduction function of Fe₃O₄, which effectively separates the hole-electron and sufficiently utilizes the photogenerated carriers for generating more active radicals. The results showed that when the content of Fe₃O₄ is 10%, the CdS/Fe₃O₄/g-C₃N₄ exhibited superior activity. The best degradation rate constant K in the like-Z-scheme photocatalyst is approximately 26 times of pure g-C₃N₄. The important role of Fe₃O₄ and the photocatalytic mechanism are also discussed in detail. This work not only puts forward a novel design idea of the like-Z-scheme material, but also is expected to be widely applied to the universal removal of kinds of antibiotics according to the practical requirement.