In-situ synthesis of direct Z-scheme 2D/2D ZnIn2S4@CeO2 heterostructure toward enhanced photodegradation and Cr(VI) reduction

The rationally designed semiconductor photocatalytic materials have attracted significant attention because of their huge advantages in the use of solar light. Herein, a series of direct Z-scheme heterojunction nanocomposites were synthesized via in situ growth of zinc indium sulfide nanosheets on ceria nanosheets (ZnIn2S4@CeO2) and employed for effective photodegradation and Cr(VI) reduction. Advanced characterizations such as XPS, EPR spectra, and DFT calculations verified that the formation of direct Z-scheme charges transfer mechanism promoted rapid charge separation and retained strong redox capacity. As a result, the optimized ZnIn2S4@CeO2 sample showed significantly promoted photocatalytic removal rates for tetracycline (TC) and Cr(VI) at a 3.7 and 4.5 times enhancement by comparison with the pristine ZnIn2S4, respectively. Additionally, after four consecutive cyclic tests, the as-synthesized nanocomposite exhibited remarkable photocatalytic activity and stability. The present work provides an integrated engineering strategy for Z-scheme photocatalyst systems with high photocatalytic efficiency and extensive applications.