Principle of CoS2/ZnIn2S4 heterostructure effect and its mechanism of action in a visible light-catalyzed antibacterial process

Abstract

The development of visible-light-driven catalytic antimicrobial technology is a significant challenge. In this study, heterojunctions were constructed for the appropriate modification of semiconductor-based photocatalysts. A simple hydrothermal method was used for material reconstruction, and smaller CoS₂ nanoparticles were deposited and in situ grown on two-dimensional nanoflower-like ZnIn₂S₄ carriers to form CoS₂/ZnIn₂S₄ (CS/ZIS) Schottky heterojunctions. Systematic study via characterization techniques and density functional theory calculations indicated that the excellent photocatalytic activity of CS/ZIS stemmed from the solid interfacial coupling between the two solid-phase materials. These materials acted as co-catalysts to increase the number of active reaction sites, enhance charge transfer, drive unidirectional electron movement, and improve charge separation efficiency, which effectively facilitated the production of reactive oxygen species (ROS). The optimized CS/ZIS heterojunction exhibited excellent performance for the efficient photocatalytic degradation of organic matter and inactivation of Escherichia coli (E. coli) compared with the ZnIn₂S₄ photocatalyst. Moreover, the antibacterial mechanism of the heterojunction photocatalyst and the extent of damage to the cell membrane and internal cytoplasm were explored by performing various assays. It was demonstrated that superoxide radicals are the predominant active species and multiple ROS act together to cause oxidative stress damage and cell inactivation.

Keywords: CoS(2)/ZnIn(2)S(4); Density functional theory calculations; Photocatalytic antibacterial; Reactive oxygen species; Schottky heterojunctions.