Boosting interfacial charge separation and photocatalytic activity of 2D/2D g-C3N4/ZnIn2S4S-scheme heterojunction under visible light irradiation

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 similar to 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. (C) 2021 Published by Elsevier B.V.

Automated summary

The study demonstrated the effectiveness of improving photocatalytic degradation performance by constructing S-scheme heterojunction photocatalysts and successfully synthesized 2D/2D CN/ZIS with different mass ratios. The heterojunction exhibited strong visible light absorption and photo-generated carriers transfer ability, achieving high degradation efficiency of tetracycline under visible light irradiation with stable photocatalytic activity.