There is an increasing need for simple and reliable procedure for characterization of photocatalytic activities of developed materials. The aim of this work was to develop a method for the determination of quantum yields of supported photocatalysts by employing an aqueous solution of coumarin. Coumarin is oxidized in the presence of irradiated TiO2 to 7-hydroxycoumarin, which could be fluorimetrically detected at low concentrations. Additionally, also a newly defined parameter, so called mass efficiency, was introduced as an advantageous way of defining the photocatalytic activities.
COBISS.SI-ID: 1064187
Dielectric properties of the new potential photocatalytic pyrochlores compositions from Bi2O3-Nb2O5-NiO system were analyzed. The dielectric properties are dominated with low-temperature relaxation phenomenon that is typical for Bi-pyrochlores and can be described by the existing relaxation model. A vast pyrochlore homogeneity range that exists in this system allowed to correlate characteristics of the observed relaxations with the compositional variations within the A2O’- and B2O6 - pyrochlore sublattice.
COBISS.SI-ID: 1099259
The modification of titania with zirconia has been found to influence the specific surface area, anatase crystallite sizes and natural hydrophilicity of the sol–gel films, but on photocatalytic activity it did not have a significant positive effect. Zirconia at a content of 10% with respect to titania was found to be homogeneously distributed along the film thickness. The films treated at low temperatures were found to have superior efficiency towards degradation of an azo dye aqueous solution since sufficient crystallinity was developed already during the sol formation.
COBISS.SI-ID: 1104123
Nowadays, it is a great challenge to synthesize crystalline TiO2 using low-temperature methods. In this study, the anatase TiO2 powders were synthesized using titanium tetrachloride as a precursor via the sol–gel method at low-temperature preparation conditions. Perchloric acid and nitric acid were used as peptizing mediators. The remaining acid in the powders prevented the aggregation of particles in the aqueous solution. Using HClO4 resulted in smaller aggregated colloidal particles, which was the main reason for better photocatalytic activity compared to the HNO3-based powder.
COBISS.SI-ID: 1103867
This work was devoted to the investigation of photoinduced superhydrophilicity (PSH) and photocatalytic oxidation (PCO) activity of quasi-2D zinc oxide nanoplatelets obtained by chemical vapor deposition. In the case of PCO, the degradation of a fatty compound layer (methyl stearate) was chosen as a test reaction. The peculiar textural and morphological features of such systems resulted in a PSH behavior and in a PCO activity appreciably higher than those of a reference commercial Pilkington ActivTM Glass.
COBISS.SI-ID: 1103611