Symbiotic composite composed of MoS2 and pelagic clay with enhanced disinfection efficiency

Abstract

Molybdenum disulfide (MoS₂) has attracted increasing attention as a promising photocatalyst. In addition to its application in photocatalytic hydrogen production and pollutant degradation, MoS₂ is also used in water disinfection. However, its poor disinfection performance limits its practical utility. Herein, we prepared a symbiotic composite composed of MoS₂ and pelagic clay (MoS₂/PC) as a photocatalyst for water disinfection. The composite achieved a high disinfection rate of 99.95% to Escherichia coli (E. coli) under visible light illumination, which is significantly higher than that of bulk MoS₂ (61.87%). Characterization shows that abundant hydroxyl groups in illite/montmorillonite (I/M) formed during hydrothermal synthesis of MoS₂, which contributed to the enhanced disinfection activity. Those hydroxyl groups can attract photogenerated holes through electrostatic attraction, and facilitate the separation of photogenerated charge carriers, thereby enhancing the disinfection activity. Moreover, the good hydrophilicity of pelagic clay improves the dispersity of MoS₂ in water, which is beneficial for its utility in aqueous solutions. In addition, the symbiotic structure restricts the growth and aggregation of MoS₂ nanosheets and shortens the diffusion distance of charge carriers to the material surface, further reducing the recombination of electrons and holes. This study provides a way to improve the disinfection activity of MoS₂ and also sheds light on high value-added utilization of pelagic clay.