• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.138-147
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• 2008

$SiO_2/TiO_2/ZrO_2$ broadband anti-reflective multi-layer thin films were prepared at room temperature by RF sputtering system. Optical constants and structural properties on each layer of films were analyzed by spectroscopic ellipsometer and transmittance spectra of the films were measured by $UV-V_{is}$ spectrophotometer in the range of 300$\sim$900 nm. To evaluate the films, we compared the measured and analyzed spectra with designed spectra. We investigated influence of discrepancy of thickness and refractive indices of each layer on changes of the transmittance spectra. It was found that refractive indices and shape of dispersion of deposition materials are more contributed to changes of the transmittance spectra than thickness of layer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1302-1307
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• 2006

This study describes the preparation of high-performance photocatalyst and its environmental applications. We prepared visible-light response nano-particle photocatalyst exhibiting the similar photocatalytic activity with $TiO_2$, dispersed $TiO_2$ on $SiO_2$ with an active rutile type titanium oxide prepared at low temperature. The binder and stable photocatalytic $TiO_2$ sol for photocatalytic system were also prepared. Such products were evaluated by UV/Vis spectrometer, X-ray diffraction analysis, SEM, measurement of photocatalytic activities and surface area, mechanical properties of $TiO_2$-coated surfaces. The results obtained can be applied in efficient photocatalytic systems using POF and metal plate for the purification of air.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.05a
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• pp.316-319
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• 2004

• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.98-103
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• 2011

Photocatalysis using UV light and catalysts is an attractive low temperature and non-energy- intensive method for remediation of a wide range of chemical contaminants like chloroform (CF). Recently development of environmental friendly and sustainable catalytic systems is needed before such catalysts can be routinely applied to large-scale remediation or drinking water treatment. Titanium dioxide is a candidate material, since it is stable, highly reactive, and inexpensive. Diatoms are photosynthetic, single-celled algae that make a microscale silica shell with nano scale features. These diatoms have an ability to biologically fabricate $TiO_2$ nanoparticles into this shell in a process that parallels nanoscale silica mineralization. We cultivated diatoms, metabolically deposited titanium into the shell by using a two-stage photobioreactor and used this biogenic $TiO_2$ to this study. In this study we evaluated how effectively biogenic $TiO_2$ nanoparticles transform CF compared with chemically-synthesized $TiO_2$ nanoparticlesthe and effect of pretreatment of diatom-produced $TiO_2$ nanoparticles on photocatalytic transformation of CF. The rate of CF transformation by diatom-$TiO_2$ particles is a factor of 3 slower than chemically-synthesized one and chloride ion production was also co-related with CF transformation, and 79~91% of CF mineralization was observed in two $TiO_2$ particles. And the period of sonication and mass transfer due to particle size, evaluated by difference of oxygen tention does not affect on the CF transformation. Based on the XRD analysis we conclude that slower CF transformation by diatom-$TiO_2$ might be due to incomplete annealing to the anatase form.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.325-325
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• 2013

본 연구에서는 선형 대향 타겟 스퍼터(Linear Facing Target Sputtering: LFTS) 시스템을 이용하여 성막한 Ti-doped In2O3 (TIO) 투명 전극의 전기적, 광학적 특성을 연구하였다. LFTS 시스템을 이용하여 유리기판 위에 TIO 박막을 증착시킬 때, 타겟과 기판 사이의 거리(Target-to-Substrate Distance)를 30 mm, 타겟과 타겟 사이의 거리(Target-to-Target Distance)를 65 mm, Ar/$O_2$ 가스의 비율 100：1로 각각 고정한 후, TIO 타겟에 인가되는 DC 파워와 공정압력을 변수로 TIO 박막을 하였다. LFTS 공정을 이용한 TIO 투명전극의 성막 공정 중 DC파워와 공정압력 변화에 따른 구조적, 표면적 특성 변화는 field-effect scanning electron microscopy (FE-SEM) 과 x-ray diffractometry (XRD) 분석을 통해 관찰되었다. 이렇게 증착된 200 nm 두께의 TIO 투명전극은 급속열처리 시스템으로 700도에서 후 열처리를 진행하였으며 상온에서 217.5 ohm/sq의 면저항을 나타내는 TIO박막이 열처리후 35 ohm/sq로 면저항이 급격히 감소됨을 확인하였다. 뿐만 아니라 열처리후 가시광선 영역 (400~800 nm)에서의 TIO 박막의 평균 투과율이 81.02%에서 83.4%로 향상됨을 UV/visible spectrometry 분석을 통해 확인하였다. 본 연구에서는 다양한 분석을 통해 TIO 박막의 특성과 ITO와 구별되는 다양한 장점을 소개한다.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.184-187
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• 2004

고급산화법 중 하나인 광촉매인 TiO$_2$를 이용한 시스템은 300~400nm 파장의 UV영역에서 비교적 적은 에너지로 유기 오염 물질을 $CO_2$와 $H_2O$로 산화시킨다[1]. 따라서 폐수용액 중 오염물질을 제거한 경우에도 슬러리로 인한 2차 오염의 문제가 없다. 최근에는 난분해성 물질이나 독성을 가진 물질을 포함된 폐수처리 시설의 고도처리를 위하여 분리막을 도입하는 추세이다.(중략)

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.231-231
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• 2011

본 연구에서는 co-sputtering 시스템을 이용하여 아나타세 TiO2의 도핑 농도 변화에 따른 다성분계 TiO2-ITO (TITO) 박막의 전기적, 광학적, 구조적 특성 변화 및 급속 열처리(RTA) 공정에 따른 전기적, 광학적 특성 변화를 분석하였다. 실험을 위해 아나타세 TiO2 타겟과 ITO 타겟(10 wt% $SnO_2$ doped $In_2O_3$)이 tilted cathode에 장착되었으며, ITO 타겟의 인가전류를 120 W로 고정한 채 아나타세 TiO2 타겟의 인가전류를 증가시킴으로써 도핑 농도를 변화하였다. 제작된 TITO 투명 전극의 전기적, 광학적, 구조적 특성 평가를 위해 four-point probe measurement, Hall effect measurement, UV/Vis. spectrometry, scanning electron microscopy (SEM) 이용하여 각각의 특성을 분석하였다. 상온에서 제작된 TITO의 경우 최적화된 $TiO_2$ 인가전류 100W에서 460.8 ohm/sq. 의 전기적 특성과 가시광선 영역 400~550 nm에서 85% 이상의 광학적 투과율을 확보할 수 있었다. 뿐만 아니라 상온에서 최적화된 TITO 투명 전극의 급속 열처리 시 600$^{\circ}C$ 급속 열처리 조건에서 매우 낮은 25.94 ohm/sq.면저항, $5.1{\times}10^{-4}$ ohm-cm 비저항과 81% 투과율을 확보할 수 있었다. 아나타세 $TiO_2$가 도핑된 TITO 투명 전극의 급속 열처리 공정에도 불구하고 매우 평탄한 표면을 나타냄을 SEM 이미지를 통하여 확인할 수 있었다. 이러한 TITO 투명 전극의 우수한 전기적, 광학적, 구조적 특성은 indium saving 투명 전극으로써 고가 ITO 박막의 대치가능성을 나타낸다.

• Membrane Journal
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• v.14 no.2
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• pp.149-156
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• 2004

This work focused on the degradation of natural organic matter (NOM) present in lake water using a combined pkotocatalysisimicrofiltration (MF) process. The system performances were investigated in terms of organic removal efficiency and membrane permeability. The addition of iron oxide particles (IOP) into the photocatalytic membrane reactor improved initial NOM removal by sorption, but during photocatalysis the removal efficiency was reversed, probably due to the scattering of UV light by IOP. The modification of TiO$_2$ surfaces by IOP deposition was conducted to enhance the photocatalytic NOM removal efficiency. A minimal amount of Impregnation of IOP on TiO$_2$ surfaces was required to prevent the light scattering effect as well. The coating of MF membranes with IOP helped to improve the NOM removal efficiency while sorbing NOM by IOP. Regardless of tile operating conditions and particles addition examined, no significant fouling was occurring at a flux of 15 L/$m^2$-h during entire MF operation.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.297-302
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• 2013

Enhancement of photocatalytic activity of UV/photocatalysis was carried out to oxidize the gaseous $H_2S$ in a tubular reactor coated with photocatalyst of sol type $TiO_2$. EtOH was used as the standard material to select the photocatalyst, and it was confirmed that the reactor activity was dependent on the coated surface characteristics. The selected photocatalytic reactor, which coated with STS-01, showed about 80% conversion when the gas linear velocity was 0.01 m/s and relative humidity was 40%. However, the conversion level of the reaction decreased significantly with increasing gas linear velocity. Pt was loaded on the photocatalyst to enhance and maintain the performance of the reactor, which enhanced the conversion level of $H_2S$ more than 95% under the same experimental condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1579-1582
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• 2007

The purpose of this study is to compare degrading performance of organic contaminants in aqueous solution using photocatalyst and find an optimal condition for decomposing non-degradable matters. The parameters of this research is light intensity and state of photocatalytic material within reactor. The results showed that Type 3 (terms of plastic beads : $500^{\circ}C$, 3hr) has the greatest reactivity.