• Korean Journal of Materials Research
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• v.11 no.9
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• pp.751-758
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• 2001

Anatase $TiO_2$ thin films as a photocatalyst were prepared by the D.C reactive magnetron sputtering process. The $TiO_2$ thin films were deposited on Si(100) substrates under the various conditions : oxygen partial pressure, working pressure, substrate temperature, D.C power, and deposition time. The morphology of the TiO$_2$ thin films showed an island structure. At early stages of film growth, amorphous phase formed. However, during the further growth, columnar crystalline $TiO_2$grains evolved. The crystallinity of the thin films depended on the oxygen partial pressure, the working pressure and the D.C. powers.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.40.1-40.1
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• 2000

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.47.1-47
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• 2002

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.53.1-53
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• 2003

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.05a
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• pp.33-41
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• 1993

The objectives of this experiment performed were to determine the potential using of solar radiation to destroy organic contaminants in water by photolysis and to develop the process and improve its performance. We used lab, scale of recirculation photoreactor with 30, 50, 80ppm initial concentration of TCE and Ti $O_2$ anatase, respectively. Adsorption constant, reaction constant were obtained and compared using the Langmuir-Hinshelwood kinetics equation. Ti $O_2$ anatase demonstrated the highest conversion ratio co TCE among Ti $O_2$ anatase, ZnO and F $e_2$ $O_3$ in this experiment. It was shown that in case of two component system, TCE+ phenol, as the concentration of phenol increased in the feed solution, TCE decomposition rate decreased.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.261-268
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• 2018

To prepare mesoporous $TiO_2$ ($meso-TiO_2$) with anatase and rutile crystal structures, hydrothermal and template synthesis were used. $Meso-TiO_2$ with anatase structure was obtained by hydrothermal synthesis. The crystal structure of $meso-TiO_2$ by hydrothermal synthesis converted from anatase to rutile by simple heating at $600^{\circ}C$ and above. However, their mesopore structure collapsed due to phase transition. To prepare $meso-TiO_2$ with rutile structure, template synthesis method was applied using mesoporous silica KIT-6 as a template. Once we incorporated anatase $TiO_2$ inside mesopores of silica, the phase transition temperature of $TiO_2$ confined inside KIT-6 was much higher ($900^{\circ}C$) than that of free-standing $TiO_2$ ($600^{\circ}C$). The suppression of $TiO_2$ phase transition inside mesopores of KIT-6 is closely related with the interaction between $TiO_2$ surface and silica walls in KIT-6 because oxygen vacancy in $TiO_2$ is regarded as the starting point for phase transition. After removal of silica template by NaOH solution washing, $meso-TiO_2$ with mixed phase between anatase and rutile was obtained.

• Solar Energy
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• v.12 no.3
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• pp.10-20
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• 1992

In this experiment, photochemical reaction has been applied to destroy TCE in water phase. The main target of this work is to investigate the technical feasibility of large scale of solar detoxification reactor for water treatment. The results have revealed that solar detoxification utilizing photon energy from the sun is the most attractive process to decompose organic toxins in water phase at room temperature. The detailed results from this work are as follows; (1) The highest conversion ratio of TCE was obtained by using $TiO_2$, annatase as a photocatalyst among $TiO_2$ anatase, $TiO_2$ rutile and $V_2O_5$ under the same experimental condition. The anatase crystal structure was confirmed with XRD analysis, and its surface area was 7.748 $m^2/g$ from the BET-$N_2$ measurement (2) 0.1 wt% of $TiO_2$ anatase has been adopted as optimal quantity for batch slurry reactor at this experimental conditions. (3) The effect of hydrogen peroxide on the conversion of TCE was investigated. Its optimal quantity was 0.06 vol. % under this experimental conditions. (4) The effect of oxygen on the conversion of TCE also was studied by controlling the head space in photoreactor. Results indicated that sufficient amount of oxygen should be supplied to accomplish the highest conversion rate of TCE in water phase.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.45-50
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• 2006

Oxygen-deficient anatase and rutile titanium dioxide $(TiO_{2-\delta})$ thin films were prepared by a sol-gel method and their structural, electronic, and magnetic properties were investigated. Both anatase and rutile $TiO_{2-\delta}:Fe$ Fe films exhibited ferromagnetism at room temperature for a limited range of Fe doping. For the same amount of Fe doping, the anatase sample exhibited a higher magnetic moment than the rutile one. Result of conversion electron Mossbauer spectroscopy measurements indicates that $Fe^{3+}$ ions substituting the octahedral $Ti^{4+}$ sites mainly contribute to the room-temperature ferromagnetism. Some of the anatase $TiO_{2-\delta}:Fe$ films exhibited p-type character but the observed feromagnetism turns out to be independent of the hole concentration. The room-temperature ferromagnetism can be explained in terms of a direct ferromagnetic coupling between two neighboring $Fe^{3+}$ ions via an electron trapped in oxygen vacancy in $TiO_{2-\delta}:Fe$.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.114.2-114
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• 2000

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.325-331
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• 2016

Anatase particles of titanium dioxide were prepared from $TiCl_4$ aqueous solution by using an electro-dialysis [ED] process. For the preparation of an aqueous solution of $TiCl_4$ precipitates, $TiCl_4$ liquid frozen in ice was transferred to a neck flask and then hydrolyzed using deionized [DI] $H_2O$. During the hydrolysis of the $TiCl_4$ solution at $0^{\circ}C$, a slurry solution of $TiOCl_2$ was obtained and the color changed from red to orange. The ED process was applied for the removal of chlorine content in the slurry solution. Two kinds of hydrolyzed slurry solution with lower [$Ti^{4+}$] and higher [$Ti^{4+}$] were sampled and the ED process was applied for the samples according to the removal time of [$Cl^-$]. With de-chlorination, the solution status changed from sol to gel and the color quickly changed to blue. Finally, white crystalline powders were formed and the phase was confirmed by XRD to be anatase crystallites. The morphology of the hydrous titania particles in the solution was observed by FE-SEM. The hydrous titania particles were nano-crystalline, and easily coagulated with drying.