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Optimizing the Au Particle Doping Size for Enhanced Photocatalytic Disinfection under Low-Intensity Visible Light.
Gi Byoung Hwang1, Ki Joon Heo2, Woongkyu Jee1
1Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
ACS Nano
|July 24, 2025
Summary
Gold nanoparticles (Au NPs) ≤ 6.3 nm enhance charge carrier transfer in crystal violet, boosting photocatalytic disinfection. This leads to potent Staphylococcus aureus inactivation under low visible light, promising self-sterilizing surfaces.
Area of Science:
- Materials Science
- Photocatalysis
- Nanotechnology
Background:
- Crystal violet (CV) is a dye used in various applications.
- Visible light photocatalysis offers a sustainable approach for disinfection.
- Gold nanoparticles (Au NPs) can act as cocatalysts in photocatalytic systems.
Purpose of the Study:
- To investigate the effect of gold nanoparticle size on charge carrier transfer and photocatalytic activity.
- To understand the mechanism of enhanced disinfection against Staphylococcus aureus.
- To explore the potential of gold nanoparticle-modified surfaces for self-sterilizing applications.
Main Methods:
- Synthesis and characterization of gold nanoparticles of varying sizes (1.2-9.9 nm).
- Spectroscopic analysis (UV-Vis, fluorescence) to study charge carrier dynamics.
- Density Functional Theory (DFT) computations to elucidate electronic band structure changes.
- Photocatalytic disinfection assays against Staphylococcus aureus under low-intensity visible light.
Main Results:
- Gold nanoparticles ≤ 6.3 nm significantly promoted charge carrier transfer from crystal violet to Au NPs.
- Reduced particle size altered the electronic band structure and charge carrier transfer pathway in crystal violet.
- 1.2 nm Au NPs maximized the generation of reactive oxygen species (ROS) and showed potent disinfection activity.
- A 5.3 log reduction in viable Staphylococcus aureus was achieved within 6 hours under low visible light flux.
Conclusions:
- Gold nanoparticle size critically influences charge carrier transfer and photocatalytic efficiency.
- 1.2 nm Au NPs act as effective cocatalysts, enhancing visible light-driven disinfection.
- This research provides insights for developing light-activated self-sterilizing surfaces for pathogen control.
