• 한국재료학회지
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• 제31권6호
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• pp.353-366
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• 2021

In this study, photocatalytic degradation of ammonia in petrochemical wastewater is investigated by solar light photocatalysis. Two-dimensional ultra-thin atomic layer structured MoS₂ are synthesized via a simple hydrothermal method. We examine all prepared samples by means of physical techniques, such as SEM-EDX, HRTEM, FT-IR, BET, XRD, XPS, DRS and PL. And, we use fullerene modified MoS₂ nanosheets to enhance the activity of photochemically generated oxygen (PGO) species. Surface area and pore volumes of the MoS₂-fullerene samples significantly increase due to the existence of MoS₂. And, PGO oxidation of MB, TBA and TMST, causing its concentration in aqueous solution to decrease, is confirmed by the results of PL. The generation of reactive oxygen species is detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). It is found that the photocurrent density and the PGO effect increase in the case with modified fullerene. The experimental results show that this heterogeneous catalyst has a degradation of 88.43% achieved through visible light irradiation. The product for the degradation of NH₃ is identified as N₂, but not NO^2- or NO^3-.

• 대한화학회지
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• 제61권4호
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• pp.179-184
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• 2017

본 논문은 $ZnO/SiO_2$를 나노 복합체(nano-compositions : NCs) 크기로 상온에서 화학적 방법으로 합성하였다. ZnO는 초음파 합성법으로 제조를 하였으며, $SiO_2$는 침전 방법을 이용하여 제조 하였다. $ZnO/SiO_2$의 구조적인 특성을 파악하기 위해 X-선회절 분석기(XRD), 주사전자현미경(FE-SEM), 푸리에 변환 적외선 스펙트럼(FT-IR)를 이용하여 $ZnO/SiO_2$가 형성되는 것을 확인 할 수 있었다. 광촉매적 특성을 판단하기 위해 $SiO_2$의 농도별로 제조된 $ZnO/SiO_2$를 Rhodamine-B 시약을 이용하여 광촉매 특성을 평가하였다. 그 결과 $SiO_2$의 농도가 증가할수록 광촉매 특성이 증가하는 것을 확인하였다. 그리고 $ZnO/SiO_2$를 가지고 항균성 실험을 진행하였다. 실험에 사용된 균(cell)은 대장균(E. coli)과 황색포도상구균(S. aureus)이다. 표면의 $SiO_2$층에 따른 항균 성실험을 진행한 결과 $SiO_2$ 층이 증가 할수록 항균 효과가 증가하는 것을 확인 할 수 있다.

• 한국지반환경공학회 논문집
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• 제24권3호
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• pp.23-27
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• 2023

흑연질화탄소(g-C₃N₄)는 가시광선 조사 하에서 항생제 분해에 효과적인 광촉매로 사용되어 왔다. 그러나 정공-전자쌍의 빠른 재결합은 광분해 효율을 제한하였다. 본 연구에서는 Ag를 마이크로파 보조 분해 방법에 의해 g-C₃N₄/g-C₃N₄ iso-type 이종 접합 광촉매에 결합시켰다. X선 회절분석, UV-DRS, FT-IR, PL 분석을 통해 이종접합의 구조와 물성을 규명하였고, Ag 장식 g-C₃N₄/g-C₃N₄ 이종접합 광촉매는 g-C₃N₄/g-C₃N₄ iso-type 이종접합 및 벌크 g-C₃N₄ 보다 우수한 성능을 보여주었다. Ag 장식 이종 접합 광촉매는 210분 이내에 가시광선 조사 하에서 설파메톡사졸 분해를 하여 우수한 광촉매 활성을 나타냈다. g-C₃N₄에 Ag의 첨가는 가시광선 흡수 범위를 넓히고 표면 플라즈몬 공명으로 인해 정공-전자쌍의 재결합을 제한하여 광촉매 활성을 향상시키는 것을 알 수 있었다.

• 한국세라믹학회지
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• 제46권3호
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• pp.234-241
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• 2009

In this study, CNT/$TiO_2$ composites derived from various titanium alkoxides and multiwalled carbon nanotubes (MWCNTs) were synthesized and characterized. Surface areas and pore volumes of the CNT/$TiO_2$ samples showed catastrophic decrease due to deposition of titanium compounds. Scanning electron microscopy (SEM) results indicated that the MWCNTs were homogenously decorated and well-dispersed onto/into the composites without apparent agglomeration of $TiO_2$ particles. In the X-ray diffraction (XRD) patterns, peaks of anatase and rutile phase were observed. The energy dispersive X-ray spectroscopy (EDX) spectra revealed the presence of major elements such as C and O with strong Ti peaks. According to the photocatalytic results, MB removal by a treatment with CNT/$TiO_2$ composites seems to have an excellent removal effect as order of CTIP, CTNB and CTPP composites due to a photolysis of the supported $TiO_2$, the radical reaction and the adsorptivity and absorptivity of the MWCNTs.

• 전기화학회지
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• 제3권2호
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• pp.81-84
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• 2000

This article deals with various photochemical processes occurring at $TiO_2$ surface and its applications in practical living conditions. In the first part, we present an overview of $TiO_2$ photocatalysis under weak W illumination with a special emphasis on bactericidal and detoxification properties of $TiO_2$ films. The second part deals with the photoinduced super hydrophilic TiCt surftce which has a wide commercial applications. In the last part, we present our recent work on boehmite-based super hydrophobic surfaces containing small amount of $TiO_2$ to obtain self-cleaning effect.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.314-315
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• 2004

As environmental issue threatens to be aggravated, applications of bio-degradable plastic (Polybutylene Succinate:PBS) tend to be increased. However, improvement of mechanical characteristics of PBS is indispensable for further widespread actual applications. Therefore, in order to produce further functional P8S with improved mechanical characteristics, TiO$_2$ coatings on PBS substrate were prepared under various spraying conditions using plasma and HVOF spraying techniques. The effects of thermal spraying methods and spraying parameters on coating properties could be confirmed. Moreover, wear behavior for TiO$_2$ coatings on PBS substrate has been also reviewed and characterized.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.90-90
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• 2010

We investigated the modification of optical response properties of titanium dioxide (TiO2) coatings on the ceramic water-purification filters by using ultraviolet-visible absorption spectroscopy and X-ray diffraction. The TiO2 coatings were prepared on ceramic substrate by e-beam evaporation method. These amorphous TiO2 were turned into anatase phase by heat treatment at $700^{\circ}C$ for 2 hours. The doping of N atoms into the TiO2 coatings was done by using 70KeV of N＋ ion implantation with the dose of $1.0{\times}1017$ ions/cm2, followed by post-irradiation heat treatment at $550^{\circ}C$ for 2 hours. Methylene blue test of TiO2 coatings to solar irradiation showed that the post-evaporation heated TiO2 was photocatalytic and N-doped TiO2 reacted to the visible part of solar irradiation.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.367-370
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• 2015

Monolayer transition metal dicalcogenide (TMDC) materials are currently attracting extensive attention due to their distinctive electronic, transport, and optical properties. For example, monolayer $MoS_2$ exhibits a direct band gap in the visible frequency range, which makes it an attractive candidate for the photocatalytic water splitting. For the photoelectrochemical water splitting, the appropriate band edge positions that overlap with the water redox potential are necessary. Similarly, appropriate band level alignments will be crucial for the light emitting diode and photovoltaic applications utlizing heterojunctions between two TMDC materials. Carrying out first-principles calculations, we here investigate how the band edges of $MoS_2$ can be adjusted by surface ligand functionalization. This study will provide useful information for the realization of ligand-based band engineering of monolayer $MoS_2$ for various electronic, energy, and bio device applications.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.955-956
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• 2006

Fe-doped $TiO_2$ nanopowders were prepared by mechanical alloying (MA) varying Fe contents up to 8.0 wt.%. The UV-vis absorption showed that the UV absorption for the Fe-doped powder shifted to a longer wavelength (red shift). The absorption threshold depends on the concentration of nano-size Fe dopant. As the Fe concentration increased up to 4 wt.%, the UV-vis absorption and the magnetization were increased. The benefical effect of Fe doping for photocatalysis and ferromagnetism had the critical dopant concentration of 4 wt.%. Based on the UV absorption and magnetization, the dopant level is localized to the valence band of $TiO_2$.

• 대한화학회지
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• 제53권5호
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• pp.560-564
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• 2009

용액침전법에 의해 ZnO 및 $Zn_{0.95}Mn_{0.05}O$를 제조하였다. Mn이 5% 치환된 ZnO 시료는 순수한 ZnO의 띠 간격인 3.37 eV (380 nm 흡광)로부터 1.50 eV (800 nm 흡광)까지 띠 간격이 줄어들게 되어 자외선 영역 뿐 아니라 가시광선 전체 영역에서도 흡광이 발생하였다. 가시광선에서의 광촉매 활성에서도 $Zn_{0.95}Mn_{0.05}O$ 시료는 P-25보다도 더 높은 활성도를 나타냈다.