Binary Co@ZF/S@GCN S-scheme heterojunction enriching spatial charge carrier separation for efficient removal of organic pollutants under sunlight irradiation

The hydrothermal approach was used to create a binary Co@ZF/S@GCN step-scheme (S-scheme) photocatalyst system. Cutting-edge devices such as TEM, XRD, XPS, FTIR, BET, UV–vis, transient photo-response, ESR signals, and EIS were used to analyze the hybrid photocatalyst. Combining 5% Co-doped zinc ferrite (Co@ZF) nanoparticles (NPs) with varying amounts (10–80 wt%) of S-g-C₃N₄ (S@GCN) yielded a series of binary nanocomposites (NCs). For photocatalytic dye removal, novel binary NCs built between Co@ZF and S@GCN create an enormous number of catalytic active positions. The results demonstrated that loading 5% Co@ZF NPs on S@GCN, which functions as a well-defined heterointerface for adequate charge transit and separation over the S-scheme Co@ZF/S@GCN NCs, resulted in a well-defined heterointerface. The loading of 5% Co@ZF NPs supports enhancing the BET surface area of the binary system for the photocatalytic response, boosting the sunlight harvesting capability and thereby improving the photocatalytic activity of the system. The binary hybrid photocatalyst system with optimal loading of 50% Co@ZF NPs showed the highest photo-removal efficiency (99%), which is about 2.5 times higher than those of their counterparts. Moreover, the trapping experiments revealed that •OH^- and h⁺ were the main active species in the process of MB aqueous photo-degradation.