• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.193-198
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• 2015

Ceria supported on various commercial $TiO_2$ catalysts were prepared by wet-impregnation method. We confirmed that the correlation between physicochemical properties of $TiO_2$ supports and SCR activities. Physicochemical properties of the various $TiO_2$ were evaluated using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, X-ray photoelectron spectroscopy (XPS), and pH analysis. Ce/Ti catalyst exhibited different SCR activities with respect to physicochemical properties of $TiO_2$. An excellent activity was obtained as the surface area of $TiO_2$ increased. In the case of CeOx surface density, the excellent activity in a range of $2.5{\sim}14.5CeOx/nm^2$ was achieved and the activity tended to decrease above $14.5CeOx/nm^2$. The O/Ti mole ratio of $TiO_2$ in the range of 1.32 to 1.79 showed an excellent SCR activity. It was also confirmed that the pH of the $TiO_2$ has no effects on the SCR activity. In order to achieve excellent SCR activities, ceria oxide should be supported on $TiO_2$ possessing a high specific surface area and certain O/Ti mole ratio. In addition, the catalyst with the low CeOx surface density resulted from the high dispersed ceria oxide should be prepared.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.240-248
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• 2002

$Fe_xTi_{l-x}O_2$ films (x=0.07 and 0.16) were grown by oxygen-plasma-assisted molecular beam epitaxy on rutile $TiO_2$(110). The same growth conditions were applied for both films in order to determine surface characteristics of grown films as a function of Fe composition. The films were characterized by several surface analysis techniques. The oxidation states of Ti and Fe in $Fe_xTi_{l-x}O_2$ films were found to be +4 and a mixture of +2 and +3, respectively. More $Fe^{3+}$ species exist in higher Fe doped film of $Fe_{0.16}Ti_{0.84}O_2$. The morphology of $Fe_{0.07}Ti_{0.93}O_2$ film shows tall rectangular and cylinderical islands growth on flat substrate-like surface. On the other hand, $Fe_{0.16}Ti_{0.84}O_2$ film consists of round shaped small islands showing somewhat rougher surface compared to the surface of $Fe_{0.16}Ti_{0.84}O_2$ film.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.154-159
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• 1997

Hydorthemal coating technique has been sucessfully applied to improve oxidation resistance of graphite by forming rutile-TiO2 layer. Hydrothermal treatment of graphite in 0.2M TiCl4 aquous solution at 35℃ resulted in improved water wettability due to the formation of surface-modifying TiO2. The amount of TiO2 increased with temperature. In the presence of surface TiO2 layer, weight loss was reduced by 30%, while the initiation temperature of oxidation was lowered by 30℃.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.147-148
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• 2007

The compound, Ti3(Al,Si)C2, was synthesized by hot pressing a powder mixture of TiCX, Al and Si. Its oxidation at 900 and 1000 oC in air for up to 50 h resulted in the formation of rutile-TiO2, -Al2O3 and amorphous SiO2. During oxidation, Ti diffused outwards to form the outer TiO2 layer, and oxygen was transported inwards to form the inner mixed layer.

• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.383-390
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• 2002

To investigate behaviors of Ti and O elements and microstructures of anodic titanium oxide films, the films were prepared by anodizing pure titanium in $H_2$S $O_4$, $H_3$P $O_4$, and $H_2O$$_2$ mixed solution at 180V. The microstructures and chemical states of the elements were analyzed using SEM, X-ray mapping, AFM, XRD, XPS (depth profile). The films formed on a titanium substrate showed porous layers which were composed of pore and wall, And with increasing anodizing time a hexagonal shape of cell structures were dominant and solace roughness increased. From the XRD result the structure of the Ti $O_2$ layer was anatase type of crystal on the whole. In the XPS spectra it was found that Ti and O were chemically binded in forms of Ti $O_2$, TiOH, $Ti_2$ $O_3$ at Ti 2p, and Ti $O_2$, $Ti_2$ $O_3$, $P_2$ $O_{5}$, S $O_4^{2-}$ at O ls respectively. Concentration of Ti $O_2$ decreased as the depth increased from the surface of the oxide film towards the substrate, but to the contrary concentrations of TiOH and $Ti_2$ $O_3$ increased.d.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.130.1-130.1
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• 2013

We made attempts to improve photocatalytic activity of $TiO_2$ nanoparticles under visible light exposure by combining two additional treatments. N-doping of $TiO_2$ by ammonia gas treatment at $600^{\circ}C$ increased absorbance of visible light. By coating thin film of polydimethylsiloxane (PDMS), and subsequent vacuum-annealing at $800^{\circ}C$, $TiO_2$, became more hydrophilic, thereby enhancing photocatalytic activity of $TiO_2$. Four types of $TiO_2$ samples were prepared, bare-$TiO_2$, hydrophilic-modified $TiO_2$ ($h-PDMS/TiO_2$), N-doped $TiO_2$ ($N/TiO_2$) and hydrophilic-modified and N-doped $TiO_2$ ($h-PDMS/N/TiO_2$). Adsorption capability was evaluated under dark condition and photocatalytic activity of $TiO_2$ was evaluated by photodegradation of MB under blue LED (400 nm< ${\lambda}$) irradiation. N-doping on $TiO_2$ was characterized using XPS and hydrophilic modification of $TiO_2$ surface was analyzed by FT-IR spectrometer. It was found that N-doping and hydrophilic modification both had positive effect on enhancing adsorption capability and photocatalytic activity of $TiO_2$ at the same time. Particularly, N-doping enhanced visible light absorption of $TiO_2$, whereas hydrophilic surface modification increased MB adsorption capacity. By combining these two strategies, photocatalytic acitivity under visible light irradiation became the sum of individual effects of N-doping and hydrophilic modification.

• Macromolecular Research
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• v.17 no.3
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• pp.174-180
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• 2009

Chemical modification of titanium/titanium oxide (Ti/$TiO_2$) substrates has recently gained a great deal of attention because of the applications of Ti/$TiO_2$-based materials to biomedical areas. The reported modification methods generally involve passive coating of Ti/$TiO_2$ substrates with protein-resistant materials, and poly(ethylene glycol) (PEG) has proven advantageous for bestowing a nonbiofouling property on the surface of Ti/$TiO_2$. However, the wider applications of Ti/$TiO_2$ based materials to biomedical areas will require the introduction of biologically active moieties onto Ti/$TiO_2$, in addition to nonbiofouling property. In this work, we therefore utilized surface-initiated polymerization to coat the Ti/$TiO_2$ substrates with polymers presenting the nonbiofouling PEG moiety and subsequently conjugated biologically active compounds to the PEG-presenting, polymeric films. Specifically, a Ti/$TiO_2$ surface was chemically modified to present an initiator for atom transfer radical polymerization, and poly(ethylene glycol) methacrylate (pEGMA) was polymerized from the surface. After activation of hydroxyl groups of poly(pEGMA) (pPEGMA) with N,N'-disuccinimidyl carbonate, biotin, a model compound, was conjugated to the pPEGMA films. The reactions were confirmed by infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle goniometry, and ellipsometry. The biospecific binding of target proteins was also utilized to generate micropatterns of proteins on the Ti/$TiO_2$ surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.5
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• pp.294-297
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• 2016

Titanium oxide ($TiO_2$) thin films were fabricated by unbalanced magnetron (UBM) sputtering. The fabricated $TiO_2$ films were treated by oxygen plasma under various RF powers. We investigated the characteristics of oxygen plasma treatment on the surface, structural, and physical properties of $TiO_2$ films prepared at various plasma treatment RF powers. UBM sputtered $TiO_2$ films exhibited higher contact angle value, smooth surface, and amorphous structure. However, the rms surface roughness $TiO_2$ films were rough, and the contact angle value was decreased with the increase of the plasma treatment RF power Also, the hardness value of $TiO_2$ film as physical properties was slightly increased with the increase of the plasma treatment RF power. In the results, the performance of $TiO_2$ films for self cleaning critically depended on the with the plasma treatment RF power.

• Journal of the Korean institute of surface engineering
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• v.34 no.2
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• pp.135-141
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• 2001

Arc-melted Ti-6Al-4V, Ti-4Fe and Ti-(1,2) Si alloys were oxidized at 700, 800, 900 and $1000^{\circ}C$ in air. The oxidation resistance of Ti-4Fe was comparable to that of Ti-6Al-4V, while the oxidation resistance of Ti-(1,2) Si was superior to that of Ti-6Al-4V. Ti-2Si displayed the best oxidation resistance among the four alloys, but failed after oxidation at $1000^{\circ}C$ for 17h. The oxide scale formed on Ti-6Al-4V, Ti-4Fe and Ti-(1,2)Si consisted of ($TiO_2$ and a small amount of $Al_2$$O_3$), ($TiO_2$ and a small amount of dissolved iron), and ($TiO_2$ plus a small concentration of amorphous $SiO_2$), respectively. The oxide grains of the surface scale of the four alloys were generally fine and round.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.7
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• pp.440-444
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• 2016

Titanium oxide ($TiO_2$) thin films were synthesized on polymer insulator and Si substrates by atomic layer deposition (ALD) method. The surface and electrical properties of $TiO_2$ films synthesized at various ALD cycle numbers were investigated. The synthesized $TiO_2$ films exhibited higher contact angle and smooth surface. The contact angle of $TiO_2$ films was increased with the increase of ALD-cycle number. Also, the rms surface roughness of films was slightly rough with the increase of ALD-cycle number. The leakage current on $TiO_2$ film surface synthesized at various conditions were uniformed, and the values were decreased with the increase of ALD-cycle number. In the results, the performance of $TiO_2$ films for self-cleaning critically depended on a number of ALD-cycle.