Boosting interfacial charge separation and photocatalytic activity of 2D/2D g-C3N4/ZnIn2S4 S-scheme heterojunction under visible light irradiation

•2D–2D S‑scheme g-C3N4/ZnIn2S4 heterostructure photocatalyst was prepared by a simple hydrothermal method.•The g-C3N4/ZnIn2S4 system exhibited outstanding photodegradation performances by used tetracycline.•The S-scheme charges transfer of g-C3N4/ZnIn2S4 photocatalyst for promoting catalytic performance was discussed.•The improved catalytic activity was ascribed to excellent redox capability of g-C3N4/ZnIn2S4 system. The prepared visible-light driven 2D/2D S-Scheme g-C3N4/ZnIn2S4 heterojunction shows plenty of ZnIn2S4 nanosheets are directional grown on the g-C3N4, along with high-efficiency photodegradation activity during TC under visible light irradiation. [Display omitted] It was an effective strategy to improve photocatalytic degradation performance by constructing step-scheme (S-scheme) heterojunction photocatalysts with superior photo-redox capacity and high charge transfer efficiency. In this study, two-dimensional/two-dimensional (2D/2D) S-scheme g-C3N4/ZnIn2S4 (CN/ZIS) heterojunction with different mass ratios were synthesized by the hydrothermal method. Transmission electron microscopy (TEM) analysis showed that ZnIn2S4 nanosheets with an average size of ~20 nm were coupled on the surface of ultra-thin graphitic carbon nitrogen (g-C3N4) nanosheets, which can effectively increase the contact area. UV–vis diffuse reflectance spectra (DRS), Photoluminescence spectra (PL) and photochemical tests showed that CN/ZIS had strong visible light absorption ability and photo-generated carriers transfer ability. Under visible light irradiation, CN/ZIS-10 degraded 93.41% of tetracycline (TC), which was 1.38 times than that of pristine g-C3N4. Moreover, the photocatalytic activity of CN/ZIS-10 was almost no change after five cycles. The S-scheme mechanism of CN/ZIS-10 was explored through electron spin response (ESR) and capture experiments of active species. In conclusion, this work provided a reasonable example for the construction of g-C3N4-based S-scheme heterojunction.