Novel fabrication of the recyclable MoS2/Bi2WO6 heterostructure and its effective photocatalytic degradation of tetracycline under visible light irradiation

Developing cost-effective and highly effective visible-light-driven photocatalysts for decomposition of organic contaminants has been deliberated as an important and viable strategy for environmental remediation. Herein, MoS2/Bi2WO6 heterostructure photocatalysts were fabricated with excellent visible light absorption performance and efficient electron/hole (e-/h+) separation efficacy. As-prepared all photocatalysts were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high resolution TEM, X-ray photoelectron spectroscopy (XPS). Although photocatalytic experiments were examined by UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence spectroscopy (PL), and transient photocurrent (I-t). Among all the photocatalysts, that synthesized by using the components 10 mg of Bi2WO6 with 100 mg of MoS2 (denoted as MSBW-10), displayed high photocatalytic performance (96.31%) for tetracycline (TC) under visible light irradiation within 90 min. The kinetic rate constant of the MSBW-10 heterostructure was 5.51 and 6.71 times higher than those of MoS2 and Bi2WO6, respectively. Further, radical trapping experiments revealed that OH radicals and holes were the predominant reactive species involved in the photocatalytic course. The recycle tests revealed the stability of the photocatalyst, which exhibited 91.85% TC removal efficacy without obvious decay even after the fourth cycle. Furthermore, the type-II MoS2/ Bi2WO6 heterostructure photocatalyst exhibited a slighter band gap with energy band alignments and enhanced visible-light absorption, separation of charge carriers, and good oxidation/reduction capacities. These deeper insights and synergetic effects can afford a new approach for flourishing novel heterostructure photocatalysts.

Automated summary

In this study, cost-effective and highly effective visible-light-driven photocatalysts, MoS2/Bi2WO6 heterostructure photocatalysts, were successfully fabricated. The photocatalysts demonstrated excellent visible light absorption performance and efficient electron/hole separation efficacy. The MoS2/Bi2WO6 heterostructure photocatalyst synthesized with 10 mg of Bi2WO6 and 100 mg of MoS2 showed the highest photocatalytic performance for tetracycline decomposition under visible light irradiation. The photocatalyst also exhibited a smaller band gap, enhanced visible-light absorption, and efficient charge carrier separation.