Visible light driven MoS₂/α-NiMoO₄ ultra-thin nanoneedle composite for efficient Staphylococcus aureus inactivation

Area of Science:

• Materials Science
• Photocatalysis
• Environmental Science

Background:

• Multidrug-resistant bacteria pose a significant threat to public health.
• Developing efficient and environmentally friendly methods for bacterial inactivation is crucial.

Purpose of the Study:

• To synthesize a novel MoS₂/α-NiMoO₄ nanocomposite for photocatalytic inactivation of multidrug-resistant bacteria.
• To elucidate the mechanism of bacterial inactivation under visible light irradiation.

Main Methods:

• Microwave hydrothermal synthesis of MoS₂/α-NiMoO₄ ultra-thin nanoneedle composite.
• Visible light irradiation for photocatalytic inactivation experiments.
• Electron spin resonance (ESR) and radical trapping experiments to identify active species.
• Transmission electron microscopy (TEM) for morphological analysis.
• Electrochemical techniques (transient photocurrent, EIS, CV) to evaluate charge separation.

Main Results:

• The MoS₂/α-NiMoO₄ composite completely inactivated Staphylococcus aureus within 150 minutes under visible light.
• Superoxide radicals (O₂¯) were confirmed as the major active species.
• Evidence of bacterial membrane damage, DNA fragmentation, and protein destruction was observed.
• The composite exhibited enhanced ROS production, efficient electron-hole separation, and superior photocatalytic activity compared to the host material.
• TEM confirmed bacterial inactivation by ROS, not photocatalyst toxicity.

Conclusions:

• The synthesized MoS₂/α-NiMoO₄ nanocomposite is a highly effective visible-light photocatalyst for inactivating multidrug-resistant bacteria.
• The mechanism involves ROS generation, leading to bacterial cell membrane damage, DNA fragmentation, and protein degradation.
• This composite shows great potential for application in treating biological wastewater contaminated with resistant bacteria.