• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.815-818
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• 2008

Titanium was oxidized with oxygen plasma and calcinated with rapid thermal annealing for degradation of humic acid dissolved in water. Titania photocatalytic plate was produced by titanium surface oxidized with oxygen plasma by Plasma Enhanced Chemical Vapor Deposition(PECVD). RF-power and deposition condition is controlled under 100 W, 150 W, 300 W and 500 W. Treatment time was controlled by 5 min and 10 min. The film properties were evaluated by the X-ray Photoelectron Spectroscopy (XPS) and X-Ray Diffraction (XRD). From the experimental results, we found the optimal condition of titania film which exhibited good performance. Moreover photocatalytic capacity was about twice better than thermal spray titania film, and also as good as titania powder.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.553-554
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• 2007

By sol-gel method, we have fabricated silica-titania hybrid film using silane treated colloidal $TiO_2$ and characterized the film through FT-IR, TGA, UV-VIS and AFM. The silica-titania hybrid film showed Ti-O-Si chemical bond at FT-IR peak of $910{\sim}940cm^{-1}$. The fabricated hybrid film showed thermal stability of around $350^{\circ}C$(5wt% loss temperature) and transparency more than 90%. In addition, the good surface smoothness was confirmed by AFM. Therefore, the silica-titania hybrid film with outstanding properties can be potential for application in electronics and displays.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.257-257
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• 2012

Cerium doped anatase titania powders were prepared by sol-gel process, with ammonium (IV) nitrate and Titanium (IV) butoxide as the raw materials. The characteristics of anatase $TiO_2$ and cerium doped $TiO_2$ were investigated by XRD, DTA, FE-SEM and UV/Vis spectroscopy. Research results indicated that XRD data characteristic diffraction peaks of anatase phase and also showed that cerium phase was not observed. Moreover XRD and DTA results imply that the addition of cerium to titania modifies the mechanism of formation of the titania phases.

• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.80-85
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• 1991

Laser Raman spectroscopy has been used to study the tungsta catalyst supported on titania. The surface tungsten species which forms on titania after calcination appeared to possess a structure that is independent of the initial impregnation condition. The surface polytungstate seemed to be stable only at the interfacial region since the crystalline WO$_3$ phase was observed as long as the tungsta loading was in excess of monolayer coverage. The close intact and strong interaction between the polytungstate and the titania could be evidenced from the inhibition of the phase transition of TiO$_2$ from anatase to rutile.

• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.138-143
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• 1991

Laser Raman spectroscopy has been used to study the interaction of $MoO_3$ with $TiO_2$. The bulk molybdenum oxide appeared to spread on the surface of titania under the submonolayer coverage. The surface polymolybdate was observed to be very stable with respect to the repeated treatment of reduction and subsequent calcination. Owing to the interaction of molybdate and titania, the phase transformation of $TiO_2$ seemed to be strongly retarded. The additives such as Co and Ni reacted readily with $MoO_3$ to form the corresponding molybdate salts. Nevertheless, the polymolybdate species appeared to be more stable on the titania surface than the molybdate salts.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.05a
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• pp.151-154
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• 2001

• Advances in materials Research
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• v.1 no.4
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• pp.311-347
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• 2012

Infections are caused due to the infiltration of tissue or organ space by infectious bacterial agents, among which Staphylococcus aureus bacteria are clinically most relevant. While current treatment modalities are in general quite effective, several bacterial strains exhibit high resistance to them, leading to complications and additional surgeries, thereby increasing the patient morbidity rates. Titanium dioxide is a celebrated photoactive material and has been utilized extensively in antibacterial functions, making it a leading infection mitigating agent. In view of the property amelioration in materials via nanofication, free-standing titania nanofibers (pure and nominally doped) and nanocoatings (on Ti and Ti6Al4V implants) were fabricated and evaluated to assess their efficacy to mitigate the viability and growth of S. aureus upon brief (30 s) activation by a portable hand-held infrared laser. In order to gauge the effect of exposure and its correlation with the antibacterial activities, both isolated (only titania substrate) and simultaneous (substrate submerged in the bacterial suspension) activations were performed. The bactericidal efficacy of the IR-activated $TiO_2$ nanocoatings was also tested against E. coli biofilms. Toxicity study was conducted to assess any potential harm to the tissue cells in the presence of photoactivated materials. These investigations showed that the photoactivated titania nanofibers caused greater than 97% bacterial necrosis of S. aureus. In the case of titania-coated Ti-implant surrogates, the bactericidal efficacy exceeded 90% in the case of pre-activation and was 100% in the case of simultaneous-activation. In addition to their high bactericidal efficacy against S. aureus, the benignity of titania nanofibers and nanocoatings towards tissue cells during in-vivo exposure was also demonstrated, making them safe for use in implant devices.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.35.1-35
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• 2000

• Advances in nano research
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• v.1 no.2
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• pp.71-82
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• 2013

A simple chemical precipitation technique is reported for the synthesis of a hybrid nanostructure of single-wall carbon nanotubes (SWCNT) and titania ($TiO_2$) nanocrystals of average size 5 nm, which may be useful as a prominent photocatalytic material with improved functionality. The synthesized hybrid structure has been characterized by transmission electron microscopy (HRTEM), energy-dispersive X-ray analysis (EDAX), powder X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. It is clearly revealed that nearly monodispersed titania nanocrystals (anatase phase) of average size 5 nm decorate the surfaces of SWCNT bundles. The UV-vis absorption study shows a blue shift of 16 nm in the absorbance peak position of the composite material compared to the unmodified SWCNTs. The photoluminescence study shows a violet-blue emission in the range of 325-500 nm with a peak emission at 400 nm. The low temperature electrical transport property of the synthesized nanomaterial has been studied between 77-300 K. The DC conductivity shows semiconductor-like characteristics with conductivity increasing sharply with temperature in the range of 175-300 K. Such nanocomposites may find wide applications as improved photocatalyst due to transfer of photo-ejected electrons from $TiO_2$ to SWCNT, thus reducing recombination, with the SWCNT scaffold providing a firm and better positioning of the catalytic material.

• Journal of the Korean Ceramic Society
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• v.56 no.4
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• pp.374-386
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• 2019

A process for nitrogen doping of TiO₂ ceramics was developed, whereby polycrystalline titania particles were prepared at 450-1000℃ with variation of the firing schedule under N₂ atmosphere. The effect of nitrogen doping on the polycrystallites was investigated by X-ray diffraction (XRD) and Raman analysis. The microstructure of the TiO₂ ceramics changed with variation of the firing temperature and the firing atmosphere (N₂ or O₂). The microstructural changes in the nitrogen-doped TiO₂ ceramics were closely related to changes in the Raman spectra. Within the evaluated temperature range, the nitrogen-doped titania ceramics comprised anatase and/or rutile phases, similar to those of titania ceramics fired in air. Infiltration of nitrogen gas into the titania ceramics was analyzed by Raman spectroscopy and XRD analysis, showing a considerable change in the profiles of the N₂-doped TiO₂ ceramics compared with those of the TiO₂ ceramics fired under O₂ atmosphere. The nitrogen doping in the anatase phase may produce active sites for photocatalysis in the visible and ultraviolet regions.