Cu-Doped TiO2: Visible light assisted photocatalytic antimicrobial activity
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Date
2018-10-26
Authors
Mathew, Snehamol
Ganguly, Priyanka
Rhatigan, Stephen
Kumaravel, Vignesh
Byrne, Ciara
Hinder, Steven J.
Bartlett, John
Nolan, Michael
Pillai, Suresh C.
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Publisher
MDPI AG
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Abstract
Surface contamination by microbes is a major public health concern. A damp environment is one of potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO2) can effectively curb this growing threat. Metal-doped titania in anatase phase has been proven as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu)-doped TiO2 (Cu-TiO2) was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO2 was carried out via sol-gel technique. Cu-TiO2 further calcined at various temperatures (in the range of 500–700 °C) to evaluate the thermal stability of TiO2 anatase phase. The physico-chemical properties of the samples were characterized through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV–visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO2 was maintained well, up to 650 °C, by the Cu dopant. UV–vis results suggested that the visible light absorption property of Cu-TiO2 was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasize the introduction of Cu+ and Cu2+ ions by replacing Ti4+ ions in the TiO2 lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9999%) was attained in 30 min of visible light irradiation by Cu-TiO2.
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Keywords
Cu-doped TiO2 , Doping , Phase transition , Escherichia coli , Staphylococcus aureus , Photocatalysis , Antibacterial coatings
Citation
Mathew, S., Ganguly, P., Rhatigan, S., Kumaravel, V., Byrne, C., Hinder, S., Bartlett, J., Nolan, M. and Pillai, S., 2018. Cu-doped TiO2: visible light assisted photocatalytic antimicrobial activity. Applied Sciences, 8(11), (2067). DOI:10.3390/app8112067