• 제목/요약/키워드: Visible-light irradiation

검색결과 225건 처리시간 0.025초

인지질(DOPC)과 지방산(8A5H)의 혼합 LB막의 광이성질화 현상과 전기화학적 특성 (Electrochemical Properties and Photoisomerization of DOPC-8A5H Mixture Langmuir-Blogett Films)

  • 박근호;최성현;김남석;김덕술
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.874-877
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    • 2004
  • We carried out this subject to observe electrochemical properties of 1,2-dioleoyl-sn- glycero-3-phosphocholine(DOPC) mixed with fatty acid containing azobenzene group by using cyclic voltammetry with a three-electrode system, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode in $NaClO_4$ solution. We investigated the photoisomerization and electrochemical property of the organic ultra thin film of fatty acid containing azobenzene was prepared on the hydrophilic ITO(idium tin oxide) glass plate by LB method. As a result, the absorption spectra of BASH and DOPC of mixture LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150 and 200 mV/s. As a results, LB films of BASH-DMPC appeared reversible process caused by the reduction-oxidation current from the cyclic voltammogram.

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Synthesis and Characterization of a Ternary Nanocomposite Based on CdSe Decorated Graphene-TiO2 and its Application in the Quantitative Analysis of Alcohol with Reduction of CO2

  • Ali, Asghar;Biswas, Md Rokon Dowla;Areerob, Yonrapach;Nguyen, Dinh Cung Tien;Oh, Won-Chun
    • 한국세라믹학회지
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    • 제55권4호
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    • pp.381-391
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    • 2018
  • In this work, photocatalytic $CO_2$ reduction over a CdSe-graphene-$TiO_2$ nanocomposite has been studied. The obtained material was successfully fabricated via ultrasonic technique. The physical properties of the as-synthesized materials were characterized by some physical techniques. The $TiO_2$ and CdSe dispersed graphene nanocomposite showed excellent results of strong reduction rates of $CO_2$ compared to the results of bare $TiO_2$ and binary CdSe-graphene. An outstanding point of the combination of CdSe-$TiO_2$ and graphene appeared in the form of great photocatalytic reduction capability of $CO_2$. The photocatalytic activity of the asfabricated composite was tested by surveying for the photoreduction of $CO_2$ to alcohol under UV and visible light irradiation, and the obtained results imply that the as-prepared CdSe-graphene-$TiO_2$ nanocomposite is promising to become a potential candidate for the photocatalytic $CO_2$ reduction.

Photocatalytic Degradation of Oxytetracycline Using Co-precipitation Method Prepared Fe2O3/TiO2 Nanocomposite

  • Jia, Yuefa;Liu, Chunli;Li, Rong
    • Journal of Magnetics
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    • 제21권1호
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    • pp.46-50
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    • 2016
  • $Fe_2O_3/TiO_2$ nanocomposite were successfully synthesized by co-precipitation method using $Fe(NO_3)_3{\cdot}9H_2O$ and $Ti(SO_4)_2$ as raw materials. Structural and textural features of the mixed oxide samples were characterized by X-ray diffractometer, field emission scanning electron microscopy and energy-dispersive X-ray. The effects of initial concentration of oxytetracycline (OTC), different competitive ions and organics on the photocatalytic degradation rate of OTC by the $Fe_2O_3/TiO_2$ nanocomposite were analyzed under UV and visible light irradiation. The results indicate that the optimized initial concentration of OTC was 50 mg/L to achieve the best photocatalytic efficiency. $Cu^{2+}$, $NH_4{^+}$, $C_3H_8O$ and EDTA in the aqueous suspension were found to suppress the degradation rate of OTC, whereas the effect of $NO_3{^-}$ and $H_2C_2O_4$ can be ignored.

Photocatalytic activity enhancement of TiO2 with adding Zn particles

  • Seo, Hyeon Jin;Boo, Jang Heon;Jang, Hyun Woo;Kim, Mi Jeong;Boo, Jin-Hyo
    • Applied Science and Convergence Technology
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    • 제25권6호
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    • pp.162-165
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    • 2016
  • APhotocatalysis process uses ambient oxygen from air and irradiation, fundamentally UV light, to generate oxidation and reduction which can degrade almost all harmful organic and inorganic compounds to nontoxic substances. This study was focused on enhancement of photocatalytic activity which improves the photocatlytic efficiency with $TiO_2$ particle by mixing of certain amounts of Zn particles. We analyzed degradation of organic pollutant materials such as toluene and phenol with the mixed photocatalysis by using UV-visible spectrophotometer and obtained a result that photocatalytic activity is increased with increasing amount of Zn particle. Especially, in the case of $TiO_2$ (1 mmol) and Zn (0.1 mmol) mixture photocatalyst, we obtained at least 2 times higher photocatalytic activity compared with the commercially available $TiO_2$ photocatalyst (Degussa P-25), indicating that our mixed photocatalyts (Zn-doped $TiO_2$) is very effective of removing both organic dye and pollutants and the conversion rate of toluene is much faster than that of phenol.

The Photodegradation Effect of Organic Dye for Metal Oxide (Cr2O3, MgO and V2O3) Treated CNT/TiO2 Composites

  • Chen, Ming-Liang;Bae, Jang-Soon;Yoon, Hee-Seung;Lim, Chang-Sung;Oh, Won-Chun
    • Bulletin of the Korean Chemical Society
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    • 제32권3호
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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.

$Eu^{3+}$가 첨가된 광변환 유리의 특성과 효과연구 1(유리의 제조와 특성) (Characteristics of Photo-conversion Glass with $Eu^{3+}$ and Its Use 1 (Glass Production and Photo-conversion Characteristics))

  • 정헌생;안양규;길대섭
    • 한국태양에너지학회 논문집
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    • 제22권4호
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    • pp.44-50
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    • 2002
  • Photosynthesis of plants is effective in the range of 550 to 700 nm of the wavelength of solar irradiation. If the conversion of ultraviolet to the above mentioned region is possible, the photosynthesizing ability is expected to be enhanced. $Eu^{3+}$ doped soda-lime bulk and $TiO_2-SiO_2$ sol-gel coated glasses were prepared and their spectroscopic properties were studied. The absorption and emission spectra for the specimens were measured with the changes of wavelength and Eu ion concentration in the range of the wavelength of 300 to 700nm. The transmittance intensity of visible light through the bulk glass and the coated one was unchanged with the addition of Eu element. The emission spectrum intensity of $Eu^{3+}$ was found to be the maximum at 618 nm which is a transition of $^5DO{\rightarrow}^7F_2$. Additionally, it was shown that the intensity was linearly increased up to 10% of the Eu concentration.

광섬유를 이용한 광촉매 성능 측정 표준화의 이해 (Standard test method for Photocatalytic activity with optical fiber)

  • 주현규;하진욱;조덕호
    • 한국산학기술학회논문지
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    • 제6권4호
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    • pp.331-336
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    • 2005
  • 최근 일본이 광촉매 관련 제품에서의 소비자 보호를 위한 적절한 표준화 규격 제정에 강한 의욕을 보이며, 자국내 JIS 규격 외에 ISO 규격 (ISO/TC 206 fine ceramics)을 제정하기 위하여 노력하고 있다. 이에 국내에서는 산업보호 및 해외시장에서의 종속성을 벗어나기 위하여 2001년부터 선정된 분야에서의 광촉매표준화 시도가 이루어졌다. 그 중의 하나로 본 논문은 광섬유를 빛 전달 매개체와 광촉매 코팅 지지체로 이용해서 광촉매 졸을 구성하는 광촉매 자체의 유기물 분해능을 결정하는 방법을 규정하는 과정과 제안과 관련된 것이다. 이 규격은 코팅 가능한 졸이나 졸로 만들 수 있는 자외선 감응 광촉매 재료에 적용하며, 차후 가시광 및 태양광 감응 광촉매 활성 측정 및 비교에도 응용이 가능할 것으로 판단된다.

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Enhanced photocatalytic performance of magnesium-lithium co-doped BiVO4 and its degradation of methylene blue

  • Nayoung Kim;Hyeonjin Kim;Jiyu Lee ;Seog-Young Yoon
    • 한국결정성장학회지
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    • 제33권4호
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    • pp.132-138
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    • 2023
  • Doped and undoped-BiVO4 samples with different elements (Li, Mg) and amounts were synthesized with a hydrothermal method. The synthesized samples were characterized using various techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis diffusion reflectance spectroscopy (UV-Vis DRS), and photoluminescence (PL) spectroscopy. Photocatalytic activity of the samples was evaluated by measuring the degradation of methyl blue (MB) under visible light irradiation. The results indicated that the incorporation of Mg and Li into BiVO4 caused lattice distortion, the presence of surface hydroxyl groups, a narrower band gap, and a reduced recombination ratio of photo-induced electron-hole pairs. Notably, the photocatalytic activity of Mg5%-Li5% co-doped BiVO4 sample exhibited a significant improvement compared to that of undoped BiVO4 sample.

건조 황칠나무 부위별 추출물을 이용한 견직물의 염색성과 기능성 (Dyeability and Functionality of Dried Dendropanax morbiferus Extracts)

  • 강다예;이정순
    • 한국염색가공학회지
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    • 제35권2호
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    • pp.67-81
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    • 2023
  • This study aims to examine the possibility of using dried Dondropanax morbiferus extract as a functional dye. The leaves and branches of were extracted with distilled water and 30% ethanol, and the dyeability and functionality of silk fabrics were examined according to the color characteristics of the extract and dyeing conditions. As a result of analyzing the ultraviolet and visible light absorption spectrum of the extract, it was possible to confirm the peak of flavonoid belonging to polyphenol, and the peak of riboflavin expressing yellow color was confirmed. Adsorption equilibrium was observed at 4% dyeing concentration and 60 minutes of dyeing time, and as the temperature increased, dyeing amount increased without color change of Y-series. Aluminum mordanting also increased the yellow color. The color fastness of washing and UV irradiation was low, but the color fastness of rubbing was evaluated as relatively good. The silk fabric dyed with the distilled water extract of the leaves showed a 99.9% bacteriostatic reduction against Staphylococcus aureus and Klebsiella pneumoniae, showing excellent antibacterial properties.

감광제 광산화에 의한 Bisphenol A 안정성 감소 (Decreased Stability of Bisphenol A by Photosensitization)

  • 박찬억;이재환
    • 한국식품과학회지
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    • 제42권3호
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    • pp.277-280
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    • 2010
  • 내분비교란물질인 BPA는 식품의 포장용기나 젖병 등의 제조에 이용되며, 라이보플라빈 광산화에 의해 안정성이 감소하는 것으로 보고된 바 있다. 본 연구에서는 광산화 시 메틸렌블루, 로즈벵갈, 라이보플라빈, 또는 이산화티타늄 등의 감광제 종류에 따른 BPA안정성을 비교하였고, sodium azide($NaN_3$) 농도에 따른 BPA안정성을 확인하였다. BPA 농도는 라이보플라빈, 로즈벵갈, 메틸렌블루 순서로 유의적으로 감소하였지만(p<0.05), 이산화티타늄 첨가 시료와 대조구인 감광제 무첨가군의 BPA 농도는 유의적인 차이가 없었다(p>0.05). BPA의 안정성은 메틸렌블루 농도 의존적으로 감소하였으며, $NaN_3$ 농도가 증가할수록 BPA 안정성은 증가하였다. 이는 메틸렌블루 광산화에 의한 BPA농도 감소에 일중항산소가 관여함을 의미한다.