Heterojunctions based on metal layer double hydroxide with Bi2WO6 as efficient solar photocatalyst and antimicrobial agent

Abstract

Photocatalysis is a highly prospective oxidation technology for the elimination of organic and biological pollutants. There is a considerable and urgent need to develop economic treatment methods that are cost-effective and energy resilient. Herein, pure Zn–Al and Zn–Ti Layered double hydroxides (LDHs) photocatalysts and hybrid with Bi₂WO₆ were constructed using a hydrothermal process. The obtained photocatalysts were examined for their ability to disinfect gram-positive bacterial strains named Staphylococcus aureus using the agar disk diffusion approach, as well as their photocatalytic ability for photodegrading methylene blue (MB) under solar energy. The findings indicated that the obtained Zn–Ti/Bi₂WO₆ LDH nanocomposite with a mass ratio of 10 % of Bi₂WO₆ exhibited the best antibacterial efficacy against S. aureus, with a mean inhibition region diameter of 25.7 mm. Moreover, Zn–Ti/Bi₂WO₆ LDH demonstrated remarkable photodegradation of MB dye as a model pollutant compared to the other catalysts with improved photocatalytic ability of 93 %. The rate constant of Zn–Ti/Bi₂WO₆ LDH was enhanced 6 times greater than either Bi₂WO₆ or Zn–Ti LDH. There was also excellent recyclability for five consecutive runs with slightly reduction of the photocatalytic ability using the obtained Zn–Ti/Bi₂WO₆ LDH nanocomposite. Mott-Schottky plots analysis, electrochemical impedance, isoelectric point (pH_IEP), trapping experiments and bandgap calculations were performed to have a deep insight into the photocatalytic mechanism of the Zn–Ti/Bi₂WO₆ catalyst. This work could be expected to address of ultrathin S-scheme Zn–Ti/Bi₂WO₆ LDH heterostructure for developing stable and efficient photocatalysts and understanding the photocatalysis applications under solar energy.