Bilayer coatings based on silica materials and iron (III) phthalocyanine – Sensitized TiO2 photocatalyst

This study presents a sol-gel method for preparation of bilayer coatings based on silica materials and iron (III) phthalocyanine - sensitized TiO₂ nanoparticles (TiO₂–Fe(III)Pc), deposited on glass surfaces. Silica materials were synthetized using organosilane precursors (dimethoxydimethylsilane (DMDMES), octyltriethoxysilane (OTES), and/or hexadecyltrimethoxysilane (HDTMES)), with a two-step acid reaction. The materials properties have been investigated using FT-IR and UV–vis spectroscopy, AFM analysis, and water contact angle. The photo-degradation experiments of thin films were developed using methylene blue as a standard contaminant. FT-IR spectra confirmed the successful grafting of silica materials onto the surface of TiO₂–Fe(III)Pc nanoparticles. AFM analysis indicated that the thin films present a different nanostructure depending on the silica matrix and the existence of TiO₂–Fe(III)Pc nanoparticles. Contact angle measurements showed that sol-gel coatings exhibit hydrophobic behavior (>99 ± 2°), before and after photo-degradation test. The presence of nanoparticles plays an important role in the development of coatings with photo-catalytic property.