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Growth of single crystals and their basic characterization.
Hanzlíková, Kateřina ; Pospíšil, Jiří (advisor) ; Matěj, Zdeněk (referee)
Basic methods of single crystals growth have been studied in this bachelor thesis. The preparation of anatase and ruby single crystals has been realized by floating zone method in different compositions of the surrounding atmosphere. Crystallinity of prepared materials has been verified by Laue method. The same method has been used for orientation of the prepared single crystals along the principal crystallographic axes. The tetragonal structure of TiO2 has been proved by powder X-ray diffraction. The floating zone method has been found as a very suitable and effective method to grow anatase single crystals.
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Synthesis and photocatalytic applications of titanium dioxide
Solný, Tomáš ; Drbohlavová, Jana (referee) ; Vlček,, Jozef (referee) ; Ptáček, Petr (advisor)
V práci je zkoumán vliv podmínek na průběh hydrolýzy alkoxidů titanu a vlastností připravovaných nanočástic oxidu titaničitého s důrazem na teplotu a množství vody přítomné v systému. Připravované hydrolyzáty alkoxidů titanu a nanočástice oxidu titaničitého připravené z hydrolyzátů jsou studovány metodami XRD, DTA – TGA, SEM – EDS, BET a PCCS. Nanočástice magnetitu byly syntetizovány pomocí precipitační reakce z roztoku Mohrovy soli a jejich krystalová struktura, velikost a povrchové vlastnosti byly sledovány s vyhodnocením vlivu teploty a při modifikaci povrchu polykarboxyletherovým superplastifikátorem. Pro upevnění TiO2 na povrch magnetitu byla použita kombinovaná metoda aplikace vybraných nanočástic TiO2 s hydrolýzou TiO2 pomocí alkoxidů titanu za účelem přípravy fotokatalyticky aktivního core-shell práškového katalyzátoru s vylepšenými vlastnostmi adsorpce na povrchu. Studovány byly možnosti aplikace TiO2 na povrch Mn-Zn feritu, kdy byl studován vliv depozice tenkých vrstev C a Au na morfologii povrchu. Fotokatalytická aktivita vybraných připravených materiálů byla studována pomocí dekompozice methylenové modři v roztoku a par isopropanolu a ethanolu rozkládaných pomocí Mn-Zn feritu v experimentálním chemickém reaktoru s magnetickým polem stabilizovaným ložem nosiče katalyzátoru.
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Synthesis and properties of ceramic nanoparticles based on anionic doped composite oxides of titanium
Kašpárek, Vít ; Veselý, Michal (referee) ; Cihlář, Jaroslav (advisor)
Master’s thesis deals with synthesis of anatase and its anion doping by carbo-nitridation. Prepared samples were used for testing of the photocatalytic activity. Low-temperature anatase was synthesized at 80 °C for 6 hours and carbo-nitridatation was carried out in ammonia/tetrachloromethane atmosphere at 500 °C for 3 hours. The influence of silver content on low-temperature crystallization of anatase was studied by reaction of titanium tetraisopropoxide with water. Silver nanoparticles were prepared by reduction of silver nitrate by D-glukose and sodium citrate. One of the results is the draft for one-pot synthesis of anatase by titanium tetraisopropoxide with complexing agent (sodium citrate, ammonium citrate, citric acid). The study of photocatalysis water splitting was carried out in the presence of 20 % vol. of methanol. Anatase prepared with citric acid has the highest photocatalytic activity (Pt 0,5 %) in UV/VIS spectral region. The activity achieved 38,6 % effectiveness of TiO2 standard (Degussa P25). Doping by nitrogen didn’t lead to increase of photocatalytic activity.
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TiO2 pillared clay for photocatalytic purposes
Fiala, Michal ; Šoukal, František (referee) ; Ptáček, Petr (advisor)
Bachelor’s thesis describes preparation of mixed catalytic systems kaolin/ TiO2 and metakaolin/ TiO2. Samples were prepared via hydrolysis of TiCl4 in kaolin suspension. Catalyst metakaolin/ TiO2 was prepared by calcination of this material under static oven atmosphere at 600 °C. Thermal analysis (simultaneous TG-DTA), infrared spectroscopy (FT-IR) and electron microscopy (REM) were used for samples characterization. Catalytic efficiency of mixture kaolin (Sedlec Ia) or metakaolin with TiO2 (anatase) was compared with pure kaolin. Experiment is based on oxidation of ethylalcohol, which was introduced in to reactor in flow of inert gas (argon). Amount of decomposed ethylalcohol is proportion to concentration of oxygen in gas product outputting from reactor. System kaolin/ TiO2 show higher catalytic performance than metakaolin/ TiO2 catalyst.
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