• Applied Chemistry for Engineering
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• v.23 no.4
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• pp.405-408
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• 2012

$TiO_2$ particles with various shapes were synthesized by using a modified sol-gel method with binary ionic liquids. The structural properties of the particles were significantly affected by the composition of ionic liquids. This is mainly attributed to the interaction between the organic solvent and ionic liquid at the interface leading to the formation of particle structure. The photocatalytic activity of the prepared samples was also examined for the degradation of 4-chlorophenol. Among the particles, $TiO_2$ prepared with 1-octyl-3-methylimidazolium tetrafluoroborate and 1-octyl-3-methylimidazolium tetrafluoroborate showed the best photocatalytic performance.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.815-820
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• 2011

Three kinds of organometallic compounds (chromium acetylacetonate, magnesium acetate and vanadyl acetylacetonate) were used as transition metal precursor, titanium n-butoxide and multi-walled carbon nanotube as titanium and carbon precursor to prepare metal oxide-CNT/$TiO^2$ composites. The surface properties and morphology of metal oxide-CNT/$TiO^2$ composites were by Brauer-Emett-Teller (BET) surface area measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The photocatalytic activity of prepared metal oxide-CNT/$TiO^2$ composites was determined by the degradation effect of methylene blue in an aqueous solution under irradiation of visible light.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.156-161
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• 2018

$TiO_2$ photocatalyst powders were prepared by chlorination method and sol-gel method. Specific surface area and crystalline (i.e., anatase and rutile) of the catalyst varied depending on manufacture conditions and method. TTIP-sol photocatalyst had higher methylene blue (MB) decomposition characteristics than photocatalyst from chlorination method and TBOT-sol. MB removal efficiency from aqueous solution with TTIP-sol photocatalyst was over 90%. Experimental results showed that the $TiO_2$ photocatalyst with a single anatase phase and a large specific surface area had high decomposition characteristics of organic materials.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.620-626
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• 2018

Highly self-cleaning thin films of $TiO_2-SiO_2$ co-doped with Ag and F are prepared by the sol-gel method. The asprepared thin films consist of bottom $SiO_2$ and top $TiO_2$ layers which are modified by doping with F, Ag and F-Ag elements. XRD analysis confirms that the prepared thin film is a crystalline anatase phase. UV-vis spectra show that the light absorption of $Ag-F-TiO_2/SiO_2$ thin films is tuned in the visible region. The self-cleaning properties of the prepared films are evaluated by a water contact angle measurement under UV light irradiation. The photocatalytic performances of the thin films are studied using methylene blue dye under both UV and visible light irradiation. The $Ag-F-TiO_2/SiO_2$ thin films exhibit higher photocatalytic activity under both UV and visible light compared with other samples of pure $TiO_2$, Ag-doped $TiO_2$, and F-doped $TiO_2$ films.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.174-175
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• 2019

Recently, due to air pollution caused by fine dust, it is considered as a social problem. Increasing fine dust has intensified air pollution, causing many diseases and damages. This year, Seoul, South Korea, reached a severe level of fine dust pollution worldwide. The Ministry of Environment has strengthened the environmental standard for fine dust (PM2.5) from $50{\mu}g/m^3$ to $35{\mu}g/m^3$ since March 2018. When fine dust enters the human body, it causes bronchial or skin elongation such as respiratory allergies, irritable pneumonia, asthma and atopy. In this study, $TiO_2$ rutile with photocatalytic activity was used, and materials prepared by rutile sulfuric acid method were used. The photocatalytic activity rate is 95% or more and the density is $4.1g/cm^3$. The matrix was based on cement, and the substitution rate of $TiO_2$ was 0, 5, 10, 15, 20 (%). The test item is flexural strength and compressive strength.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.370.1-370.1
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• 2016

Volatile organic compounds (VOCs) are considered hazardous air pollutants and these are emitted from building materials and household products. VOCs can cause global warming as well as human sickness, and even cancer. Photocatalysis provides a way of converting VOCs into harmless materials. Various researches have shown that $TiO_2$ is the most efficient photocatalysts due to its excellent activity. In this study, metal/non-metal doped $TiO_2$ particles are synthesized for the enhancement of the photocatalytic properties of pure $TiO_2$. By metal/non-metal doping, band gap energies of prepared samples were analyzed by UV/Visible spectrophotometer. The physical and chemical properties of synthesized powder were characterized by field emission scanning electron microscope, by BET for measuring their specific surface area, and by XRD for phase identification and particle size determination. Degradation ability for p-xylene was evaluated through monitoring the concentration in a closed chamber. Relation between their properties and decomposition abilities for VOC were evaluated based on the experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.1
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• pp.63-67
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• 2021

In this paper, we investigated the surface properties of polymer insulators to improve electrical insulation performance. First, after washing the polymer insulator in various ways, its contact angle was increased, thereby improving the hydrophobic properties and electrical insulation properties. In addition, TiO2 thin films, which have been used as a photocatalytic material and have been applied to the polymer insulator surface of to enhance the surface and electrical insulating properties. For the sputtering method, the contact angle after coating the TiO2 thin film increased with increasing RF power, but it was lower compared to that before coating, indicating that the hydrophobic properties of the surface were slightly deteriorated. Consequently, the electrical properties of the polymer-insulating material were maintained or improved after the TiO2 thin-film coating.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6952-6957
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• 2014

In photocatalysis, the addition of metal matter to $TiO_2$ can alter the surface properties. As such, the metal can increase the rate of the photodegradation reaction. In this study, a range of modified $TiO_2$ photocatalysts were prepared and tested to improve the activity of photodegradation at a batch-typed photoreactor. To obtain a good sol solution of the $TiO_2$ photocatalyst, several types of dispersion agents and stabilizers were investigated. The photocatalyst solutions were modified with isoproply alcohol as the dispersion agent and sodium silicate as the stabilizer. The effects of various metallic elements on enhancing the photocatalytic activity of $TiO_2$ on the degradation of toluene were examined. Palladium-added $TiO_2$ was found to be the best, whereas copper or tungsten-added also showed good results. In the case of palladium addition, the increase in removal efficiency was 25%. On the other hand, Fe-added $TiO_2$ showed a notable decrease in photocatalytic degradation. Additional doping of copper or tungsten on the $Pd/TiO_2$ had no positive effect on the photodegradation activity.

• 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).

• Korean Journal of Materials Research
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• v.27 no.6
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• pp.325-330
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• 2017

Photoelectron-hole separation efficiency plays an important role in the enhancement of the photocatalytic activity of photocatalysts towards the degradation of organic molecules. In this study, $TiO_2/TiOF_2$ heterostructured composite powders with suitable band structures, which structures are able to separate photoelectron-hole pairs, have been synthesized using a simple and versatile ultrasonic spray pyrolysis process. In addition, their phase volume fractions have been controlled by varying the pyrolysis temperature from $400^{\circ}C$ to $800^{\circ}C$. The structural and optical properties of the synthesized powders have been characterized by X-ray diffraction, scanning electronic microscopy and UV-vis spectroscopy. The powder with a phase volume ratio close to 1, compared with single $TiOF_2$ and other composite powders with different phase volume fractions, was found to have superior photocatalytic activity for the degradation of rhodamine B. This result shows that the $TiO_2/TiOF_2$ heterostructure promotes the separation of the photoinduced electrons and holes and that this powder can be applicable to environmental cleaning applications.