Highly dispersed Zn.sub.0.5Cd.sub.0.5S nanoparticles anchored on NiCo.sub.2O.sub.4 nanosheets as the direct Z-scheme heterojunction for enhanced visible light photocatalysis

By virtue of their green and environmentally friendly properties, photocatalysis has become one of the most ideal solutions for antibiotic pollution. Herein, a series of direct Z-scheme Zn.sub.0.5Cd.sub.0.5S/NiCo.sub.2O.sub.4 photocatalysts have been successfully fabricated. The obtained Zn.sub.0.5Cd.sub.0.5S/NiCo.sub.2O.sub.4 photocatalysts displayed outstanding photocatalytic performance for tetracycline hydrochloride (TC-HCl) degradation under the irradiation of a low-energy lamp (white LED lamp, 5 W). Compared to pure Zn.sub.0.5Cd.sub.0.5S nanoparticles and NiCo.sub.2O.sub.4 nanosheets, the Zn.sub.0.5Cd.sub.0.5S/NiCo.sub.2O.sub.4 photocatalysts exhibited significantly enhanced photocatalytic activity. This pleasantly surprised result can be attributed to the formation of Z-scheme heterojunction, which effectively inhibited the recombination of electron-hole pairs and boosted the transfer efficiency of photoinduced electrons. Moreover, anchoring Zn.sub.0.5Cd.sub.0.5S nanoparticles on the surface of NiCo.sub.2O.sub.4 nanosheets can effectively reduce the aggregation of Zn.sub.0.5Cd.sub.0.5S nanoparticles and thus increase the active site. Furthermore, free radical trapping experiments confirmed that *O.sup.2- and h.sup.+ radicals play a major role in the photocatalytic process and verified the rationality of the proposed Z-scheme mechanism. Therefore, our study provides a simple strategy for the construction of direct Z-scheme system with outstanding photocatalytic performance.