Photocatalytic hydrogen evolution and antibiotic degradation by S-scheme ZnCo2S4/TiO2

In this study, ZnCo2S4 (ZCS) nanoparticles were coupled on the surface of TiO2 by simple solvothermal method to form S-scheme heterojunction. Compared with ZCS and TiO2, the photocatalytic performance of ZCS/TiO2 under simulated sunlight is significantly improved, and its hydrogen evolution efficiency reaches 5580 mu mol.g(-1).h(-1) with the apparent quantum efficiency (AQY) up to 11.5% at 420 nm, which is 88.3 times and 54.3 times that of TiO2 and ZCS, respectively. Moreover, ZCS/TiO2 also has excellent perfor-mance in the photocatalytic degradation of tetracycline (TC). The enhancement of pho-tocatalytic performance of ZCS/TiO2 is mainly due to S-scheme heterojunction. On the one hand, the S-scheme electron transfer path not only improves the electron-hole separation efficiency, but also improves the charge transfer efficiency. On the other hand, ZCS significantly enhances the visible light absorption of ZCS/TiO2. The photocatalytic mech-anism and S-scheme heterojunction structure is confirmed by XPS, EPR, ultraviolet photoelectron spectroscopy (UPS) and energy band structure. This work provides a new idea for designing and constructing S-scheme heterojunction to improve the performance of photocatalytic hydrogen evolution and TC degradation.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, ZnCo2S4 nanoparticles were coupled on the surface of TiO2 to form S-scheme heterojunction. ZCS/TiO2 exhibited significantly improved photocatalytic performance under simulated sunlight, with hydrogen evolution efficiency reaching 5580 mu mol.g(-1).h(-1) and apparent quantum efficiency (AQY) of 11.5% at 420 nm. The enhancement of photocatalytic performance was mainly attributed to the S-scheme heterojunction, which improved electron-hole separation and charge transfer efficiency, as well as enhanced visible light absorption. This work provides a new approach for improving the performance of photocatalytic hydrogen evolution and TC degradation.