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.