Cu-Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity

• Published in: Applied sciences 2018-10, Vol.8 (11), p.2067
• Main Authors: Mathew, Snehamol, Ganguly, Priyanka, Rhatigan, Stephen, Kumaravel, Vignesh, Byrne, Ciara, Hinder, Steven, Bartlett, John, Nolan, Michael, Pillai, Suresh
• Format: Article
• Language: English
• Subjects: Anatase; antibacterial coatings; Antiinfectives and antibacterials; Antimicrobial activity; Antimicrobial agents; Chemical properties; Contamination; Copper; Cu-doped TiO2; Density functional theory; doping; E coli; Efficiency; Electromagnetic absorption; Electronics industry; Escherichia coli; Hydrogen; Inactivation; Indoor air quality; Irradiation; Lattice vacancies; Light; Light irradiation; Organic chemistry; Outdoor air quality; phase transition; Phase transitions; Photocatalysis; Physicochemical properties; Public health; Raman spectroscopy; Sol-gel processes; Spectroscopy; Stability analysis; Staphylococcus aureus; Studies; Thermal stability; Titanium dioxide; X ray photoelectron spectroscopy; X-ray diffraction
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app8112067

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.