The aim of the work was to inhibit titania crystal growth at increased temperatures by doping with different ions. Cerium, silicon, and zirconium ions were used as ions for doping. Nano-titania in anatase modification using a solvothermal preparation method was synthesized. Two types of samples were prepared: (i) pure-anatase-based samples and (ii) various dopants were incorporated into the anatase. The quantity of doping has an impact on the reduction of crystal growth and stabilization of anatase crystal structure. The titania nanoparticles doped with higher proportions of Si and Zr ions keep a higher level of SSA (14.9 m2/g) in comparison with undoped samples (0.5 m2/g). Consequently such nanoparticles exhibit considerable photocatalytic activity also after heat treatment at 1050oC.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 1819751The goal was to study whether we can get photocatalytically active titania in the visible light spectrum from two precursors, namely titanium tetrachloride and titanium oxosulphate, using a simple synthesis approach. The results have shown that lowering pH and adding isopropanol to the reaction mixture before heating favor formation of the rutile phase and thus increase the photocatalytic activity in the visible light. The most photocatalytically active samples consisted of about 80% rutile and 20% anatase.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 1836391The damage of surfaces of various building objects due to exposure to harmful environmental factors can be reduced by photocatlaysis. The photocatalysts do not degrade just the organic dirt, but also organic constituents, for example organic pigments. The main goal in the present work has been to protect the organic pigment against photocatalysis by encapsulation. Detailed study on synthesis and influence of different parameters (temperature, pH) on silica encapsulation of model organic pigments was investigated. It is shown that thethickness, porosity and uniformity of silica shells (coatings) around individual pigment particles depend significantly on pH and temperature of synthesis. It is further demonstrated that the obtained silica shells can serve as an efficient protection against the highly reactive products of photocatalysis. The degree of protection depends not only on the thickness of silica shells but also on their porosity.
F.18 Transfer of new know-how to direct users (seminars, fora, conferences)
COBISS.SI-ID: 1900135We have studied the influence of selected synthesis parameters on certain key properties (phase composition, specific surface area, microstructure and photocatalytic activity) of the nanocrystalline titania that influence its photoactivity. The results have shown that pH value, starting concentration, and isopropanol addition to the reaction mixture before heating have a significant effect on the anatase:rutile ratio and consequently on morphology and particle size. By varying the anatase:rutile ratio and by doping, photocatalysts with significant activity in the visible light can be tailored. Results were presented during 20th International Conference on Materials and Technology, 17-19 October, 2012, Portorož.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 1932391During the important international conference 3rd European Symposium on Photocatalysis, September 25 27 2013, Portorož, we demonstrated the recent achievemnts in the field of self-cleaning photocatalytic materials were presented. We showed the preparation methods of new materials, the measuring techniques developed for evaluation of self-cleaning or photocatalytic efficiency and the characterization methods of the materials prepared.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 2006375