Photocatalytic Metal Oxides and Chalcogenides

Contact person: V. Štengl, Dept. Chemistry of Solids

For determination of photocatalytic activity we use stainless-steel flow-through reactors with an inner volume of 1 l. UV or Vis light sources Narva are used (e.g., Narva Blacklight Blue 365 nm, Warmwhite 827 with > 400 nm).

Solid (nanodisperse) photocatalysts are suspended in a solution with a model compound (Orange II, Rhodamin B and Reactive Black dyes are convenient for practical use). The discolouration degree is continuously determined by absorbance decrease.

For analysis of photoactive paints we have developed a method with salicylic acid decomposition, of which concentration is measured by fluorescence spectroscopy (excitation at λ_exc = 315 nm, emission maximum λ_ems = 410 nm). The layer of photoactive paint is placed in a quartz tube.

Contact person: V. Stengl, Dept. Chemistry of Solids

Special heated photoreactors with forced circulation were developed for reactions in gas/solid system. A layer of catalyst is deposited onto a glass plate with the size 10 x 15 cm with poly-hydroxyethylmetacrylate as a binder, which is permeable for gases. Butane, acetone, and ethanol are used as model organic pollutants. Approximate determination of catalytic activity is performed with gas sensors XGARD for O₂, CO₂, ethanol and propane-butane. For detailed study the reactor is connected to a gas chromatograph Agilent 6890N with a quadrupole mass spec JEOL JMS-Q100GC. That method has also been used for characterization of plasma-deposited photocatalytical coatings developed in collaboration with Institute of Plasma Physics AS CR.

• V. Stengl, V. Houskova, S. Bakardjieva et al., Photocatalytic degradation of acetone and butane on mesoporous titania layers, NEW JOURNAL OF CHEMISTRY 34(9) 1999-2005, 2010
• V. Sengl, V. Houskova, S. Bakardjieva et al., Optically Transparent Titanium Dioxide Particles Incorporated in Poly(hydroxyethyl methacrylate) Thin Layers, JOURNAL OF PHYSICAL CHEMISTRY C 112(50) 19979-19985, 2008
• Ctibor P., Stengl V., Pis, I., Zahoranova T., Nehasil V., Plasma sprayed TiO₂: The influence of power of an electric supply on relations among stoichiometry, surface state and photocatalytic decomposition of acetone, CERAMICS INTERNATIONAL 38 (4) 3453-3458, 2012