Gundars Mežinskis

Characterization of Fe2O3-TiO2 Thin Films Prepared from Sonicated and Unsonicated Sols

The development of immobilized visible light-active photocatalysts has attracted growing scientific interest due to numerous potential commercial applications. In this work sonicated and unsonicated sols were used for the development of thin films on glass substrates. The coatings were prepared using Fe2O3-TiO2 sols containing 1-5 mol% Fe2O3 and 99-95 mol% TiO2. The coatings were obtained by dip-coating method and annealed at 500 °C for 1 hour. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The ultrasound treatment of sols led to the reduction of the size of iron doped nanocrystals of TiO2 and absorption enhancement in the visible light.

Sol-Gel Synthesis of SnO2-TiO2 System - Morphologic, Photocatalytic and Antibacterial Properties

SnO2-TiO2 sol-gel coatings on soda-lime silicate glass heat treated at 500 °C and xerogel specimens also heat treated at 500 °C were investigated in this study. The morphology of 1, 3, 5 and 7 mol% SnO2 doped titanium oxide coatings were evaluated with a scanning electron microscope (SEM), an atomic force microscope (AFM) and an UV-VIS light spectrophotometer, whilst xerogel structure was analysed with X-ray diffraction spectroscopy (XRD). The physicochemical properties of the TiO2-SnO2 systems depended mainly on the Sn-to-Ti ratio. The surface morphology of the layer was compact and homogeneous with no visible cracks. Anatase and rutile phase was found in the tested 1, 3, 5, 7 and 10 mol% SnO2 doped and heat treated xerogel specimens. Rutile phase content in the heat treated xerogel was reduced, if Sn4+ content was increased. Photocatalytic activity and antibacterial properties were evaluated as well.

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.