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Self-cleaning Properties of Thin Printed Layers of Titanium Dioxide
Králová, Marcela ; Brezová, Vlasta (oponent) ; Krýsa, Josef (oponent) ; Veselý, Michal (vedoucí práce)
Titanium dioxide was immobilized on soda-lime glass substrates and glassy carbon substrates by two techniques: material printing and chemical vapour deposition. Two methods of sol preparation were used; sol-gel and hydrothermal synthesis. Morphology of all prepared titania layers were studied by scanning electron microscopy and atomic force microscopy analysis. Crystallite phase of prepared TiO2 was determined using XRD analysis. Photoinduced superhydrophilicity was examined using the sessile drop method. Photocatalytic activity was investigated as a degradation rate of 2,6-dichloroindophenol or formic acid. We studied the influence of sol-loading and amount of PEG on final activity in case of sol-gel process. PEG was added as an anticracking agent. The influence of time and temperature of hydrothermal synthesis or amount of layers on final efficiency was examined for hydrothermally synthesized samples. The influence of different intensities of irradiation was investigated for the layers deposited by CVD process. The activity of titania thin films prepared by material printing and CVD process was compared and the best sample was evaluated.
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Electrochemical, photoelectrochemical and spectroelectrochemical characterization of nanomaterials
Pitňa Lásková, Barbora ; Kavan, Ladislav (vedoucí práce) ; Šubrt, Jan (oponent) ; Krýsa, Josef (oponent)
Oxid titaničitý (TiO2) a spinel Li4Ti5O12 patří mezi široce studované polovodivé oxidy kovů. Nanokrystalické formy TiO2 a Li4Ti5O12 jsou atraktivní pro použití v lithiových bateriích a oxid titaničitý také pro fotoelektrochemické solární články. Spinel Li4Ti5O12 by díky své struktuře umožňující ukládat větší Na+ ionty (v porovnání s Li+ ionty) mohl být i slibným materiálem pro sodíkové baterie. Nanokrystalický TiO2 anatas s převládající plochou {001} byl studován elektrochemicky cyklickou voltametrií inserce lithia a chronoamperometrií a porovnán s referenčním anatasem s dominantní plochou {101}. Voltametrické a chronoamperometrické difusní koeficienty a aktivační energie prokázaly, že anatasové nanokrystaly {001}mají oproti standardním anatasovým nanočásticím vyšší aktivitu vůči inserci Li+ . Anatasové nanokrystaly TiO2 s nejvíce exponovanou plochou {101} byly následně porovnávány s nanokrystaly s dominantní plochou {001} z hlediska potenciálu rovných pásů a kinetiky elektronů. Anatasové nanodestičky {001} měly ve srovnání s anatasovými nanočásticemi {101} negativnější potenciál rovných pásů, vyšší chemickou kapacitu a delší dobu života elektronů. Ramanovou spektroskopií a in situ Ramanovou spektroelektrochemií byla studována inserce Li+ do TiO2 anatasových nanočástic. Byly připraveny a studovány...
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Self-cleaning Properties of Thin Printed Layers of Titanium Dioxide
Králová, Marcela ; Brezová, Vlasta (oponent) ; Krýsa, Josef (oponent) ; Veselý, Michal (vedoucí práce)
Titanium dioxide was immobilized on soda-lime glass substrates and glassy carbon substrates by two techniques: material printing and chemical vapour deposition. Two methods of sol preparation were used; sol-gel and hydrothermal synthesis. Morphology of all prepared titania layers were studied by scanning electron microscopy and atomic force microscopy analysis. Crystallite phase of prepared TiO2 was determined using XRD analysis. Photoinduced superhydrophilicity was examined using the sessile drop method. Photocatalytic activity was investigated as a degradation rate of 2,6-dichloroindophenol or formic acid. We studied the influence of sol-loading and amount of PEG on final activity in case of sol-gel process. PEG was added as an anticracking agent. The influence of time and temperature of hydrothermal synthesis or amount of layers on final efficiency was examined for hydrothermally synthesized samples. The influence of different intensities of irradiation was investigated for the layers deposited by CVD process. The activity of titania thin films prepared by material printing and CVD process was compared and the best sample was evaluated.
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Photoelectrochemical Oxidation of Carboxylic Acids on the Sol-Gel Thin TiO2 Layer Electrode
Morozová, Magdalena ; Klusoň, Petr ; Krýsa, Josef ; Šolcová, Olga
Heterogeneous photocatalysis is based on the reaction between the light excitated semiconductor and oxidizable compound adsorbed on the catalytic surface. This work reports the photoelectrocatalytic oxidation characteristics of carboxylic acids on the TiO2 sol-gel thin-film electrode by using electrochemical techniques. The influence of the thickness of the films on photoactivity and the various concentrations of oxalic, formic and acetic acid in the supporting electrolyte were investigated. The effect of the used mono- and dicarboxylic acids on the electrode behaviour for possible application as sensors has been also studied. The surface characteristics of TiO2 films were determined by XRD, SEM and AFM analyses and the photoexcitation properties of nanoparticulate layer electrode were determined by cyclic and linear voltammetry, amperometry and open circuit potential (OCP).
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