Enhanced photocatalytic activity of mesoporous SiO sub(2)/TiO sub(2) sol-gel coatings doped with Ag nanoparticles

• Published in: Journal of sol-gel science and technology 2015-10, Vol.76 (1), p.180-194
• Main Authors: Roldan, M V, Castro, Y, Pellegri, N, Duran, A
• Format: Article
• Language: English
• Subjects: Coatings; Multilayers; Nanoparticles; Photocatalysis; Silicon dioxide; Silver; Sols; Titanium dioxide
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-015-3765-6

In the present study, as-prepared silver nanoparticles have been incorporated into SiO sub(2) and TiO sub(2) sols. The characterisation of the silver nanoparticles was performed through transmission electron microscopy, grazing X-ray diffraction, and UV-visible spectroscopy, before and after mixing with the different sols. Multilayer coatings doped with silver nanoparticles were also prepared by combining different compositions and analysed by TEM and GXRD. The photocatalytic activity was studied through the degradation of methyl orange in aqueous solution under UV light exposure. High photocatalytic efficiency was observed for all the multilayer coatings. The highest efficiency was obtained for the Ag-SiO sub(2)/TiO sub(2) mesoporous system that reached a degradation percentage of methyl orange up to 94 % after 2.5 h of irradiation, near the complete elimination of the pollutant. The mechanism that explains the high photocatalytic efficiency of this multilayer coating is associated with the high porosity of the mesoporous coatings and with the increase in the local electric field, associated with the effect of plasmon resonance surface produced for the presence of metallic silver nanoparticles in the SiO sub(2) film. Graphical Abstract https://static-content.springer.com/image/art%3A10.1007%2Fs10971-0 1 5-3765-6/MediaObjects/10971_2015_3765_Figa_HTML.gif