Noble metal-modified octahedral anatase titania particles with enhanced activity for decomposition of chemical and microbiological pollutants

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 318; pp. 121 - 134
• Main Authors: Wei, Z., Endo, M., Wang, K., Charbit, E., Markowska-Szczupak, A., Ohtani, B., Kowalska, E.
• Format: Journal Article
• Language: English
• Published: Switzerland Elsevier B.V 15.06.2017; Elsevier
• Subjects: Antimicrobial activity; Modified titania; Octahedral anatase particles; Photocatalytic activity; Plasmonic nanoparticles; Visible light-responsive photocatalysts; Photocatalytic activity; Antimicrobial activity; Visible light-responsive photocatalysts; Modified titania; Octahedral anatase particles; Plasmonic nanoparticles
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2016.05.138

[Display omitted] •Enhancement of titania activity by modification with Au, Pt, Ag and Cu.•Significant change of properties by metal photodeposition in the presence of oxygen.•Correlation of antimicrobial and photocatalytic properties for octahedral anatase.•Zero-valent Pt and Au and positively charged Cu and Ag in the ambient environment.•Visible activity of Au/OAPs and Ag/OAPs, due to activation of plasmon resonance. Octahedral anatase particles (OAPs) were prepared by hydrothermal (HT) reaction of titanate nanowires (TNWs). OAPs were modified with noble metals (Au, Ag, Cu and Pt) by two photodeposition methods: in the absence and in the initial presence of oxygen in the system. Photocatalytic activities for oxidative decomposition of acetic acid and anaerobic dehydrogenation of methanol under UV/vis irradiation and for oxidation of 2-propanol under visible light irradiation were investigated. Antibacterial activities for bacteria (Escherichia coli) and fungi (Candida albicans) were investigated in the dark and under UV irradiation and/or visible light irradiation. It was found that the kind of metal deposition significantly influenced the properties of photocatalysts obtained and thus their photocatalytic and antimicrobial activities. Modification of OAPs with metallic deposits resulted in enhanced photocatalytic activities for all tested systems. Pt-modified OAPs showed the highest activity for dehydrogenation of methanol due to their highest work function and lowest activation overpotential of hydrogen evolution. Cu-modified OAPs exhibited the highest activity for oxidative decomposition of acetic acid under UV/vis irradiation, probably due to the heterojunction between Cu oxides and TiO2. On the other hand, Au-modified OAPs showed the highest photocatalytic activity under visible light irradiation due to their plasmonic properties. Bare OAPs, prepared with various durations of the HT reaction, did not have any antibacterial properties in the dark, while their activity under UV/vis irradiation was correlated with their photocatalytic activities for dehydrogenation of methanol and decomposition of acetic acid. Antimicrobial activity of modified OAPs in the dark and under visible light irradiation was the highest for Ag-modified OAPs. Under UV irradiation, Cu-modified OAPs showed the highest activity for inactivation of both bacteria and fungi.