Enhanced photocatalytic activity of mesoporous SiO2/TiO2 sol–gel coatings doped with Ag nanoparticles

Abstract

In the present study, as-prepared silver nanoparticles have been incorporated into SiO 2 and TiO 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 2 /TiO 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 2 film.

Photocatalytic degradation of Rhodamine B dye by cotton textile coated with SiO2-TiO2 and SiO2-TiO2-HY composites

“…The symbol (*) refers to peaks utilized to calculate the Si/Al ratios according to Section 2.2. [40,51], although the underlying mechanisms were still not fully explained. Fig.…”

Study of the characteristics and properties of the SiO2/TiO2/Nb2O5 material obtained by the sol–gel process

“…Besides this, these materials combine the mechanical properties of the silica matrix with the chemical properties of the metal oxides, exhibiting different chemical and physical properties from those observed in the oxide alone, especially because the presence of Brønsted and Lewis acid sites on the oxide mixture 3 , 4 , 11 – 14 . Hence, the oxides mixture are interesting materials for various applications 3 , 4 : as heterogeneous catalysis 2 , 9 , 15 , 16 , photoanodes for solar cells 6 , photocatalytic activity 7 , optical properties 8 , bioactive glass 10 , preconcentration systems of metallic ions 11 , 17 – 19 , dye remediation or adsorbent in aqueous solution 5 , 20 , adsorption of interest molecules 21 , development of new chemically modified electrodes 22 , 23 , among others.…”

A Facile Method with Low Hydrothermal Temperature to Synthesize TiO2 as Controlled Release Drug Delivery

“…Many methods are employed to synthesize TiO 2 , including Sol–Gel technique, hydrothermal treatment, conventional chemical precipitation, hydrolysis of titanium alkyloxide (Ti(OR) 4 ) and titanium tetrachloride (TiCl 4 ), and micro‐emulsion method . The inherent advantages and disadvantages of the above‐mentioned synthetic routes need to be clear to select a specific procedure to synthesize well‐defined products.…”