• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.311-312
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• 2002

환경분야에서 광촉매는 주로 오염물질의 광분해처리에 이용되고 있는데, 기존에 사용되고 있는 광분해 방법은 광촉매 미립자를 수용액에 슬러리 형태로 분산시키거나 fixed bed, fluidized bed에 부착시킨 형태의 반응기들이다. 실험적 수준의 연구로부터 얻어진 여러 연구 결과에 의하면 슬러리 형태의 반응기가 고정화 촉매 반응기보다 효율이 더 높은 것으로 보고되고 있다. 그러나 엔지니어링 관점에서 슬러리형 반응기는 촉매의 재활용과 정화 처리 후 촉매입자를 유체로부터 분리해야하는 결점이 있다. (중략)

• Clean Technology
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• v.21 no.3
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• pp.178-183
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• 2015

Lead molybdate (PbMoO₄) oxides were successfully synthesized using a conventional hydrothermal method and a microwave-assisted hydrothermal method. They were characterized by XRD, DRS, BET, Raman, SEM and PL. We also investigated the photocatalytic activity of these materials for the decomposition of Rhodamine B under UV-light irradiation. From XRD and Raman results, well-crystallized PbMoO₄ crystals have been successfully synthesized regardless of preparation method and had 42~59 nm particle size. The PbMoO₄ catalysts prepared using microwave-assisted process had the similar particle size and enhanced the photocatalytic activity when compared to that prepared by hydrothermal method. The PbMoO₄ catalysts prepared under the irradiation of microwave for 75 min showed the highest photocatalytic activity. The PL peaks appears at about 530 nm at all catalysts and it was also shown that the excitonic PL signal is proportional to the photocatalytic activity for the decomposition of Rhodamine B.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.66-72
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• 2008

The photocatalytic degradation of a textile diazo dye in aqueous solution has been investigated under Solar and UV-A light. The effect of various parameters such as concentration of dye, amount of catalyst and pH on the degradation of dye has been studied. Addition of hydrogen peroxide, ammonium persulphate and isopropanol strongly influences the degradation rate. Kinetic analysis of photodegradation reveals that the degradation follows approximately pseudo first order kinetics according to the Langmuir-Hinshelwood model. Carbon dioxide, nitrate and sulphate ions have been identified as mineralisation products. The photocatalyst ZnO was found to be more efficient in UV-A light than in Solar light.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.164.1-164.1
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• 2016

본 연구에서 지지체로 사용된 단결정 형태의 수산화인회석(Hydroxyapatite)은 칼슘과 인산염으로 구성된 무기물이다. 염기 조건 (10 M NaOH)에서 수열합성법 (Hydrothermal method)을 이용하여 단결정 형태의 수산화인회석을 합성하였다. 합성된 단결정 수산화인회석의 표면에 이온 교환 반응을 통하여 은 원자를 도입하였으며, 아르곤 및 수소 기류 (96% Ar, 4% $H_2$) 조건에서 가열하는 온도를 조절하는 것으로 은 나노 입자를 생성시켰다. 합성된 샘플은 XRD 패턴 및 TEM 이미지 분석을 통하여, 수산화인회석의 합성 및 은 나노 입자가 형성된 것을 확인하였다. 합성된 샘플을 유기 반응 촉매로 사용하여 여러 가지 알코올 (1차, 2차 알코올)의 산화 반응에 응용하였으며, UV-Visble light 영역에서의 메틸렌 블루 분해 반응 실험에 광촉매로서 사용하였다.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1035-1040
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• 1999

Photocatalytic degradation of trichloroethylene has been carried out with UV-illuminated $TiO_2$-coated pyrex reactor in gas phase. Three commercial $TiO_2$ oxides were used as catalysts. The effect of reaction conditions, initial concentration of trichloroethylene, concentration of oxidant and light intensity on the photocatalytic activity were examined. Anatase-type catalyst showed higher activity than rutile-type, but P-25 catalyst showed the highest activity. The degradation rate increased with the decrease of flow rate and initial trichloroethylene concentration. It was preferable to use air as an oxidant. In addition, reactants with the water vapor decreased the activity and the degradation rate increased with the increase of light intensity, but it was very low with solar light. Photocatalytic deactivation was not observed at low concentration of trichloroethylene.

• Clean Technology
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• v.25 no.2
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• pp.123-128
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• 2019

$Bi_2MoO_6$ catalysts were successfully synthesized using ethylene glycol monomethyl ether (EGME), glycerol (GL), ethylene glycol (EG), and water as solvents by a conventional hydrothermal method. The synthesized catalysts were characterized by XRD, DRS, BET, SEM, and PL, and we also investigated the photocatalytic activity of these materials for the decomposition of Rhodamin B under visible light irradiation. The XRD results revealed the successful synthesis of 12-18 nm, well-crystallized ${\gamma}-Bi_2MoO_6$ crystals with an Aurivillius structure regardless of solvent. In addition, the $Bi_2MoO_6$ catalysts prepared below $140^{\circ}C$ showed an amorphous phase; however, those prepared above $160^{\circ}C$ showed well-crystallized ${\gamma}-Bi_2MoO_6$ crystals. All the catalysts have a similar absorption spectrum from the ultraviolet region up to the visible region less than 470 nm. This result suggests that all the $Bi_2MoO_6$ catalysts are potential visible-light-driven photocatalysts. The $Bi_2MoO_6$ catalysts prepared using EGME as a solvent showed the highest photocatalytic activity. In addition, the $Bi_2MoO_6$ catalysts prepared at $180^{\circ}C$ showed the highest photocatalytic activity. The PL peaks appeared at about 560 nm at all catalysts and the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of Rhodamin B. This suggests that the stronger the PL intensity, the larger the amount of oxygen vacancies and defects, and the higher the photocatalytic activity.

• 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.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.261-263
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• 2007

본 연구는 광전자 촉매시스템을 이용해 $TiO_{2}$ 졸이 코팅된 구형 비드의 광분해 효율에 대해 고찰한 것이다. $TiO_{2}$ 졸이 코팅된 구형 비드인 알루미늄비드, 유리비드, 실리카비드 화이트젤 ($1{\cdot}2{\cdot}3$형) 다섯 가지 비드를 사용하였고 실험은 산화환원지시 약인 메틸렌블루 수용액이 광촉매의 산화환원반웅을 통해 색상 및 홉광도 변화를 통해 환원 청도를 고찰할 목적으로 실행되었다. 소재별 실험 결과, 실험에 사용한 소재 중 실리카비드 화이트첼($1{\cdot}2{\cdot}3$형)만이 반응성을 나타냈다. 이들 $1{\cdot}2{\cdot}3$형은 $TiO_{2}$의 함량을 달리한 비드들이며 1형이 가장 적은 함량을 가지며 3형이 가장 많은 함량을 가지고 있다. 실험 결과 3형이 반응성이 가장 좋은 것을 알 수 있으며, 이 실험에서는 코팅물의 함량과 고정물의 상태가 광촉매 반응에 영향을 주는 것을 알 수 있다.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.323-327
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• 2010

Ti-SBA-15 catalysts doped with lanthanide ion were synthesized using conventional hydrothermal method and they were characterized by XRD, FT-IR, DRS, $NH_3$-TPD and PL. We also examined the activity of these materials on the photocatalytic decomposition of methylene blue. La/Ti-SBA-15 samples with varying lanthanide ions doping maintained the mesoporous structure and the catalysts calcined at $500^{\circ}C$ for 6 h showed the highest crystallinity. With increasing the doping amount of lanthanide ion, the pore size and pore volume of La/Ti-SBA-15 materials decreased but the surface area increased. 1% La/Ti-SBA-15 catalysts showed the highest photocatalytic activity on the decomposition of methylene blue but the catalysts doped with more than 5% lanthanide ions showed lower activity compared to pure Ti-SBA-15 catalyst.

• Clean Technology
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• v.16 no.1
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• pp.46-50
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• 2010

This study focuses on the removal of water-suspended toluene of a representative sick house compounds in a liquid photo-system using nanometer-sized Sn-incorporated $TiO_2$ which was synthesized by a solvothermal method. The characteristics of the synthesized Sn-$TiO_2$ were analyzed by X-ray Diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), and UV-visible spectroscopy (UV-Vis). To estimate the photocatalytic activity of Sn-$TiO_2$, the photodegradation of water-suspended toluene was performed, and the remaining concentration was determined using UV-visible spectroscopy. The water-suspended toluene photodegradation over Sn-incorporated $TiO_2$ catalyst was better than that over pure $TiO_2$ (anatase). The water-suspended toluene of 500 ppm was perfectly decomposed within 300 minutes over 0.01 mol% Sn-$TiO_2$.