Ústav fyzikální chemie J. Heyrovského

Nejnovější přírůstky:
2019-08-26
09:04
THE PHOTOCATALYTIC ABATEMENT OF NOX IMISSIONS USING COMMERCIAL FUNCTIONAL COATING WITH POROUS MORPHOLOGY
Žouželka, Radek
Titanium dioxide is the most important photocatalysts used for purifying applications. It was the purpose of this study to investigate the photocatalytic activity of commercial Protectam FN (R) containing TiO2 nanoparticles towards NO and NO2. Experiments on concrete as a support for photocatalyst were carried out in two types of reactors with laminar and turbulent flow under ´´real world setting´´ conditions of temperature, relative humidity, irradiation and pollutant concentrations. The results showed that photocatalytic process significantly reduced both nitrogen oxides in the air. The decrease in the total concentration of nitrogen oxides on contact with the photocatalytic surface reached 20-50 %, i.e. at a concentration of 100 ppb the decrease in NO and NO2 was 20-50 ppb. The nitrogen oxides were oxidized up to their highest oxidation state, nitric acid ( or nitrates) and undesirable nitrous acid was not formed at all. The experimental study conducted showed that the photocatalytic oxidation on the surface of the photocatalytic Protectam FN (R) coating is an effective method for the removal of nitrogen oxides from contaminated air.

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2019-08-26
09:04
Influence of electrode preparation on electrocatalytic activity of water soluble porphyrazine complex to hydrogen
Klusáčková, Monika ; Janda, Pavel ; Tarábková, Hana
The influence of electrode preparation and used electrode substrate on electrocatalytic activity of N, N´,N´´,N´´´tetramethyl-tetra-3,4-pyridinopor-phyrazinocobalt (CoTmt-3,4-ppa) complex deposited on electrode surface for hydrogen reaction has been studied. Electrochemical deposition, spontaneous adsorption, and spin coating have been used to the modification of two different electrode substrates: annealed gold and highly oriented pyrolytic graphite. Prepared electrodes have been characterized using cyclic voltammetry, backscattering VIS spectroscopy and atomic force microscopy. The detailed comparison of surface morphology, surface coverage, surface roughness parameters, and thickness of deposited layers of CoTmt-3,4-ppa mediatoronhydrogen reaction has been investigated.

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2019-08-26
09:04
Development of the poly(methylene blue) modified graphite electrodes for the electrochemical detection of hydrogen sulphide
Zlámalová, Magda ; Janda, Pavel ; Nesměrák, K.
A comparative study have been undertaken of the electropolymerization and electrochemical properties of deposited electroactive polymer on two different graphite electrode substrates: basal plane highly oriented pyrolytic graphite (HOPG) and pencil-graphite electrode (PGE). Poly(methylene blue) modified electrodes (HOPG/pMB and PGE/pMB) have been prepared by potential cycling in aqueous electrolyte solution containing methylene blue monomer. It has been found that electrochemical properties and electrocatalytic activity of deposited film are greatly influenced by the type of electrode substrate. Developed electrodes have been further investigated as potential sensors for hydrogen sulphide.

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2019-08-26
09:04
A COMPARATIVE STUDY OF LIQUID- AND GAS-PHASE CYCLOPENTENE HYDRATION CATALYZED BY THE MCM-22 ZEOLITE
Krupka, J. ; Otmar, J. ; Pawlesa, Justyna
The study deals with technological aspects of the direct hydration of cyclopentene to cyclopentanol. The catalytic properties of the MCM 22 zeolite were studied in the case of cyclopentene hydration both in liquid and gas phases. MCM-22, unlike other solid acid catalysts, is highly selective for the formation of cyclopentanol in the liquid-phase hydration in the slurry arrangement. It suppresses completely the undesirable etherification of cyclopentanol and allows obtaining cyclopentanol with almost 99% selectivity. But the liquid-phase hydration was found to lead to rapid deactivation of the zeolite. The deactivation is caused mainly by a formation of carbon deposits in the pores of the zeolite. When hydrating in the gas phase on the fixed bed of granular catalyst, it could be easy to periodically reactivate the catalyst in situ. However, it has been found that the exceptional selectivity of MCM-22 to the cyclopentanol formation is characteristic only for the liquid-phase hydration. The reaction in the gas phase is unselective. Furthermore, the equilibrium conversion of cyclopentene to cyclopentanol in the gas-phase hydration has been found to be industrially unusable below 1 % (e.g. under atm. pressure, at 120 degrees C and with a molar ratio of cyclopentene to water 1: 5, it is as low as 0.3 %).

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2019-08-26
09:04
Electropolymerization of Methylene Blue on Highly Oriented Pyrolytic Graphite and Characterization of Deposited Film
Zlámalová, Magda ; Janda, Pavel ; Nesměrák, K.
This work presents the investigation of methylene blue (MB) polymerization as well as characterization of deposited conductive film on basal plane highly oriented pyrolytic graphite (HOPG) substrate. Poly(methylene blue) modified HOPG electrodes (HOPG/pMB) have been prepared by potential cycling in aqueous electrolyte solution containing monomer methylene blue. Atomic force microscopy (AFM) has been used for the nanomorphological study of immobilized poly(methylene blue) film.

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2019-08-26
09:04
Charge Transport through Molecular Towers Based on Tetraphenyhmethane Tripods
Kolivoška, Viliam ; Šebera, Jakub ; Lindner, M. ; Valášek, M. ; Mayor, M. ; Mészáros, G. ; Gasior, Jindřich ; Hromadová, Magdaléna
Molecular platforms with multiple anchors were introduced recently to provide robusi coupling between molecular electronic components and metallic electrodes. In this work, charge transport in tower-shaped single molecule conductors based on tetraphenylmethane tripod possessing three thiol anchors is investigated by scanning tunneling microscopy break junction technique. The effect of tripod substitution pattern and number of repeating units in molecule is addressed. The substitution was found to influence conductance value in early stages of molecular junction evolution, where tower lays parallel to surface. In late stages, the charge is transported through principal molecular axis and junction breaks thermally in tilted configuration.

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2019-07-25
09:14
Výzkumná zpráva o strukturní, morfologické a elektrochemické analýze vzorků dodaných HE3DA
Zukalová, Markéta
Zpráva obsahuje výsledky morfologické analýzy provedené na sadě dodaných vzorků a jejich elektrochemické testování.

Úplný záznam
2019-07-25
09:14
Výzkumná zpráva o strukturní, morfologické a elektrochemické analýze vzorků dodaných HE3DA
Zukalová, Markéta
Zpráva obsahuje výsledky rentgenostrukturní, morfologické a chemické analýzy provedené na sadě dodaných vzorků a jejich elektrochemické testování.

Úplný záznam
2019-07-25
09:14
Výzkumná zpráva o strukturní, morfologické a chemické analýze vzorků dodaných HE3DA
Zukalová, Markéta
Zpráva obsahuje výsledky rentgenostrukturní a morfologické analýzy provedené na sadě dodaných vzorků a jejich elektrochemické testování.

Úplný záznam
2019-07-25
09:14
Výzkumná zpráva o strukturní, morfologické a elektrochemické analýze vzorků dodaných HE3DA
Zukalová, Markéta
Zpráva obsahuje výsledky rentgenostrukturní a morfologické analýzy provedené na sadě dodaných vzorků a jejich elektrochemické testování.

Úplný záznam