• Elastomers and Composites
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• v.45 no.3
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• pp.206-211
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• 2010

Zinc oxide(ZnO) nanoparticles were synthesized by reacting an aqueous-alcoholic zinc nitrate solution to sodium hydroxide under ultrasonic irradiation at room temperature. The fullerene($C_{60}$) and ZnO nanoparticles were heated individually in an electric furnace for two hours at $700^{\circ}C$. The morphology and optical properties of the $C_{60}$ and ZnO nanoparticles were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and ultraviolet/visible (UV-vis) spectroscopy. The photocatalytic activity of the heated and unheated the $C_{60}$ and ZnO nanoparticles for the decomposition of methylene blue(MB), methyl orange(MO) and rhodamine B(RhB) was examined using UV-vis spectroscopy.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.674-679
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• 2008

$TiO_2$ impregnated stainless steel fiber photocatalysts ($TiO_2/SSF$) were fabricated to overcome inherent problems of powdery $TiO_2$ photocatalysts in water treatment. Adhesion strength of the impregnated $TiO_2$ was examined using an ultrasonic-cleaner. Photocatalytic activity was evaluated through decomposition experiment of methylene blue and formic acid. Bactericidal efficiency was evaluated through sterilization experiment of E. Coli and Vibrio Vulnificus. Adhesion strength of the impregnated $TiO_2$ was so high that more than 95% was left over even after the treatment in an ultrasonic-cleaner for 30 min. Methylene blue and formic acid were decomposed as much as 60% and 38% of the initial concentration and more than 99.9% of E. Coli and Vibrio Vulnificus were killed after 1 hour exposure to the prepared photocatalyst under UV irradiation. In the case of decomposition of formic acid, decomposition ratio increased if oxidants were added. Especially the decomposition ratio increased as high as 80% when hydrogen peroxide was added as an oxidant.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.81-81
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• 2010

Growth of TiO2 films prepared by atomic layer deposition (ALD) was studied on C fiber. Moreover, adsorption and photocatalytic decomposition of methylene blue on TiO2 thin films were studied. Preferential growth of TiO2 on steps of C surfaces could be identified by scanning electron microscopy (SEM). X-ray Photoelectron Spectroscopy (XPS) showed thickness-dependent positive core level shift of Ti, which can be interpreted in terms of enhanced final state charging for thicker films. Adsorption and photocatalytic behaviors of TiO2 thin films will be discussed in this poster.

• Journal of Powder Materials
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• v.25 no.4
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• pp.316-321
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• 2018

Composites of P25 $TiO_2$ and hexagonal $WO_3$ nanorods are synthesized through ball-milling in order to study photocatalytic properties. Various composites of $TiO_2/WO_3$ are prepared by controlling the weight percentages (wt%) of $WO_3$, in the range of 1-30 wt%, and milling time to investigate the effects of the composition ratio on the photocatalytic properties. Scanning electron microscopy, x-ray diffraction, and transmission electron microscopy are performed to characterize the structure, shape and size of the synthesized composites of $TiO_2/WO_3$. Methylene blue is used as a test dye to analyze the photocatalytic properties of the synthesized composite material. The photocatalytic activity shows that the decomposition efficiency of the dye due to the photocatalytic effect is the highest in the $TiO_2/WO_3$ (3 wt%) composite, and the catalytic efficiency decreases sharply when the amount of $WO_3$ is further increased. As the amount of $WO_3$ added increases, dye-removal by adsorption occurs during centrifugation, instead of the decomposition of dyes by photocatalysts. Finally, $TiO_2/WO_3$ (3 wt%) composites are synthesized with various milling times. Experimental results show that the milling time has the best catalytic efficiency at 30 min, after which it gradually decreases. There is no significant change after 1 hour.

• Journal of the Korean Ceramic Society
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• v.45 no.6
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• pp.324-330
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• 2008

Activated carbon/$TiO_2$ (AC/$TiO_2$) composites modified with different concentrations of Fe were prepared. The $N_2$ adsorption data showed that the composites had decreased surface area compared with the pristine activated carbon. This indicated the blocking of the micropores on the surface of AC, which was further supported by observation via SEM. XRD results showed patterns for the composites and an anatase typed titanium dioxide structure with a small part of rutile in a higher Fe concentration (> 1.0 mol/L). EDX results showed the presence of C and, O, with Ti peaks on the composites of Fe-AC/$TiO_2$ with relatively lower Ti concentration, which may be due to the higher Fe concentration incorporated into the composites. Subsequently, the photocatalytic effects on methylene blue (MB) were investigated. The improved decomposition of MB showed the combined effects of adsorptions and photodegradation. Especially, the composites modified by Fe revealed enhanced photodegradation behaviors of MB.

• Journal of Welding and Joining
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• v.21 no.4
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• pp.46-55
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• 2003

TiO$_2$-WO$_3$(8.2wt%) coatings were prepared by the APS (Atmospheric Plasma Spraying) process to clarify the relationship between the process parameters(H$_2$ gas flow rate of plasma 2nd gas and spraying distance) of the APS coating and photo-decomposition efficiency kinetics of the MB(methylene blue) aqueous solution decomposition and to understand the effect of addition of WO$_3$ on photocatalytic properties of TiO$_2$ sprayed coating. Further, the temperature and velocity of flying particles were measured by DPV-2000 to investigate the relationship between microstructure of coatings and process parameters. Properties of coatins were investigated by XRD, SEM, XPS, RAMAN, UV/VIS spectrometer. In case of the TiO$_2$-WO$_3$(8.2wt%) coating, it had a lower anatase fraction than that of pure-TiO$_2$ coatings because of flying in the higher temperature plasma plume by the heavy weight of TiO$_2$, WO$_3$. And, when WO$_3$ added powders were spayed, the doping effects of W ions substituted into the Ti ion sites was not occured during melting and solidification cycles of spraying. It was found that the addition of WO$_3$ was ineffective effective on increasing photo-decomposition efficiency of TiO$_2$ sprayed coating.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2637-2642
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• 2009

In this present paper, we prepared $MWCNT/TiO_2$ composites by using pre-oxidized multi-walled carbon nanotubes (MWCNTs) with different titanium alkoxide precursors in benzene solvent. The composites were comprehensively characterized by BET surface area, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX) and UV-Vis absorption spectroscopy. The photoactivity of the prepared materials, under UV irradiation, was tested using methylene blue (MB) in aqueous solution. Finally, according to the results of MB removal experiment, it can be considered that the MB degradation infect mainly caused by photocatalytic effect of $TiO_2$. Furthermore, the bactericidal test of the composites was also determined. It was indicated that $MWCNT/TiO_2$ composites with sunlight had greater effectiveness for B. cereus, S. aureus and E. coli than any other experimental conditions.

• Korean Journal of Materials Research
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• v.20 no.7
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• pp.345-350
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• 2010

For the present paper, we prepared MgO/MWCNT/$TiO_2$ photocatalyst by using multi-walled carbon nanotubes (MWCNTs) pre-oxidized by m-chlorperbenzoic acid (MCPBA) with magnesium acetate tetrahydrate $(Mg(CH_2COO)_2\cdot4H_2O)$ and titanium n-butoxide $(Ti\{OC(CH_3)_3\}_4)$ as magnesium and titanium precursors. The prepared photocatalyst was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The decomposition of methylene blue (MB) solution was determined under irradiation of ultraviolet (UV) light. The XRD results show that the MgO/MWCNT/$TiO_2$ photocatalyst have cubic MgO structure and anatase $TiO_2$ structure. The porous structure and the $TiO_2$ agglomerate coated on the MgO/MWCNT composite can be observed in SEM images. The Mg, O, Ti and C elements can be also observed in MgO/MWCNT/$TiO_2$ photocatalyst from EDX results. The results of photodegradation of MB solution under UV light show that the concentration of MB solution decreased with an increase of UV irradiation time for all of the samples. Also, the MgO/MWCNT/$TiO_2$ photocatalyst has the best photocatalytic activity among these samples. It can be considered that the MgO/MWCNT/$TiO_2$ photocatalyst had a combined effect, the effect of MWCNT, which could absorb UV light to create photoinduced electrons $(e^-)$, and the electron trapping effect of MgO, which resulted in an increase of the photocatalytic activity of $TiO_2$.

• Journal of Powder Materials
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• v.24 no.6
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• pp.477-482
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• 2017

Nitrogen-doped titanium dioxide (N-doped $TiO_2$) is attracting continuously increasing attention as a material for environmental photocatalysis. The N-atoms can occupy both interstitial and substitutional positions in the solid, with some evidence of a preference for interstitial sites. In this study, N-doped $TiO_2$ is prepared by the sol-gel method using $NH_4OH$ and $NH_4Cl$ as N ion doping agents, and the physical and photocatalytic properties with changes in the synthesis temperature and amount of agent are analyzed. The photocatalytic activities of the N-doped $TiO_2$ samples are evaluated based on the decomposition of methylene blue (MB) under visible-light irradiation. The addition of 5 wt% $NH_4Cl$ produces the best physical properties. As per the UV-vis analysis results, the N-doped $TiO_2$ exhibits a higher visible-light activity than the undoped $TiO_2$. The wavelength of the N-doped $TiO_2$ shifts to the visible-light region up to 412 nm. In addition, this sample shows MB removal of approximately 81%, with the whiteness increasing to +97 when the synthesis temperature is $600^{\circ}C$. The coloration and phase structure of the N-doped $TiO_2$ are characterized in detail using UV-vis, CIE Lab color parameter measurements, and powder X-ray diffraction (XRD).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3031-3038
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• 2009

Cobalt-loaded activated carbon fibers (ACFs) supported titanium dioxide ($TiO_2$) photocatalyst was developed by sol-gel method. The Co-ACFs/$TiO_2$ photocatalyst were characterized by scanning electron microscope (SEM), X.ray diffraction patterns (XRD), energy dispersive X.ray analysis (EDX) and UV-vis absorption spectroscopy. Decomposition efficiency of methylene blue (MB) solution by Co-ACFs/$TiO_2$ photocatalyst reached almost 100% under 300 min reaction. The MB molecules in the bulk solutions were supposed to be condensed around $TiO_2$ particles by adsorption of ACFs. Therefore, the photocatalyst possesses the combined effect of adsorption by activated carbon fibers and photocatalytic reactivity of $TiO_2$ on MB degradation. Due to the cobalt has electron transition effece, thus improved the photodegradation of MB solution.