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Sol-Gel Derived Au-Enriched TiO2 and TiO2-ZrO2 Photocatalysts and Their Examination in Photocatalytic Reduction of Carbon Dioxide
Matějová, Lenka ; Reli, M. ; Čapek, L. ; Matějka, V. ; Šolcová, Olga ; Obalová, L. ; Kočí, K.
Considering the aspects of preparation of gold-based photocatalysts and gold photocatalysis, it is worth a mention that it is more complicated issue than in the case of other noble metals due to the gold crystallinity. In this contribution some critical aspects of the gold photocatalysis will be discussed. Au-supported TiO2 and TiO2-ZrO2 photocatalysts and their pristine counterparts were prepared by using the sol-gel process controlled within reverse micelles environment and by impregnation under vacuum. All photocatalysts were characterized by OEA, ICP/MS, N2 physisorption, XRD, TEM/SEAD and UV-Vis. The performance of laboratory-prepared photocatalysts was examined in CO2 photocatalytic reduction and was compared with the catalytic performance of commercial TiO2 Evonic P25. Logically, the determined physicochemical and optical properties of photocatalysts were correlated with their catalytic performance and some interesting aspects of gold photocatalysis were revealed.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22013080910510 - PDF
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Super/Subcritical Fluid Extractions for Synthesis of Porous Metal Oxides
Matějová, Lenka ; Matěj, Z. ; Cajthaml, Tomáš ; Šolcová, Olga
In this study the influence of individual post-treatment steps on the crystallinity, purity and textural properties of prepared metal oxides - TiO2, ZrO2, TiO2-ZrO2 etc. in powdery form (aerogels) – has been studied. Titania and zirconia organogels were prepared as reaction semi-products of the sol-gel process controlled in reverse micellar solution of nonionic surfactant Triton X-114. in combination with a) subcritical fluid extractions (using water and subsequently methanol like pressurized solvents, SubWE/PFE) and b) calcination. The effect of various extraction conditions on textural and structural properties of metal oxides has been investigated. Besides that the reproducibility of these material properties has been also observed.
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Příprava a charakterizace tenkých vrstev oxidů zirkonu a titanu
Krejčíková, Simona ; Matějová, Lenka ; Matěj, Z. ; Jirkovský, Jaromír ; Šolcová, Olga
Titania and zirconia belong to nanoporous materials with huge application potential in photocatalysis, dye-sensitized photoelectrochemical cells, electrochromic devices, sensors and other applications, especially in the form of nanolayers. Differences in surface morfology, texture and crystallinity influence their catalytic impact. Therefore special attention is focused on the detailed textural and structural characterizations of thin titania-zirconia nanolayers prepared by sol-gel templated route.
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Strukturní studie tenkých titaničitých vrstev
Šolcová, Olga ; Matějová, Lenka ; Krejčíková, Simona ; Matěj, Z. ; Kužel, R. ; Strýhal, Z.
Our study is focused on the relationship between the number of oxyethylene units in nonionic surfactants used for preparation of a set of various titania layers by dip-coating via the sol-gel method and morphology, roughness, type of titania phase and textural properties of the prepared titania layers. Additionally, the contact angle determination as a rapid and easy method suitable for evaluation of the surface quality of the prepared titania layer has been tested, too.
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Nanoporézní vrstvy TiO2 a jejich využití
Krejčíková, Simona ; Matějová, Lenka ; Cajthaml, Tomáš ; Matěj, Z. ; Strýhal, Z. ; Šolcová, Olga
Titania that is promising as catalytic agent for removing of organic impurities from waste water and air, photovoltaic cell and pigment, were studied. Doped Titania layers deposited on various substrates were prepared by sol-gel technique. Sol was prepared by using nonionic surfactants Triton X, organic solvent, water and metal precursors. Deposited gel layers were converted to anatase layers by calcination at 400°C for 4 hours or by subcritic H2O/ supercritic CO2 extraction/ subcritic CH3OH extraction (SWE/SFE/PFE). For deeper textural and structural characterization of prepared layers nitrogen physical adsorption, XRD, AFM and SEM analyses were performed.
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