• Title/Summary/Keyword: Basic Science

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Enhanced Electrochemifluorescence and Reduction Mechanism of Acetoxy Coumarin Derivatives in Acetonitrile Solution

  • Kim, Sung-Hyun;Jung, Eun-Joo;So, Eun-Mi;Shen, Chang-Zhe;Chun, Hyun-Ja;Kim, Young-Man;Kim, Il-Kwang
    • Bulletin of the Korean Chemical Society
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    • v.27 no.9
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    • pp.1329-1334
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    • 2006

  • The electrochemical reduction of coumarin, 7-acetoxy-4-methyl coumarin (AMC), and 7-acetoxy-4-bromomethyl coumarin (ABMC), in 0.1 M tetraethyl ammonium perchlorate/acetonitrile solution was carried out by direct current, differential pulse polarography, cyclic voltammetry, and controlled potential coulometry. The electrochemical reduction of ABMC was proceeded through three steps of electron transfer coupled with the chemical reactions. The color of solution was changed to yellow when the carbonyl group was reduced during 2nd step (-1.8 volts) and independented with cleavage of bromo group. Highest fluorescence intensity showed when the electrochemical reduction of AMC was controlled at near the potential (-2.3 volts vs. Ag/AgCl).

  • https://doi.org/10.5012/bkcs.2006.27.9.1329 인용 PDF KSCI

Novel Photocatalytic and Antibacterial Activities of Three-Dimensional (3D) Polycrystalline Anatase TiO2 Structures

  • Lee, Hyun Uk;Yun, Hyung Joong;Son, Byoungchul;Seo, Jung Hye;Kim, Hyeran;Choi, Saehae;Jeon, Cheolho;Kim, Hae Jin;Lee, Jouhahn
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.635-635
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    • 2013

  • We report three-dimensional polycrystalline anatase TiO2 structures (3D a-TiO2) for environmental and bio-medical applications. The 3D a-TiO2 was synthesized without thermal treatment by the growth of rod-like polycrystals on Degussa P25 (P25) via low temperature (< $85^{\circ}C$) modified alkali hydrothermal processing. X-ray diffraction and high-resolution transmission electron microscopic results showed that the rod-like polycrystals of 3D a-TiO2 possessed the highly anatase nanostructures. The photocatalytic activity of 3D a-TiO2 was found to be 2.2 times higher than that of P25. The recyclability of the 3D a-TiO2 was found to be high: the decolorization rate was 94.8% of the initial value after fifteen cycles. In addition, 3D a-TiO2 exhibited excellent antibacterial activities for the sterilization of gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus). Even at the 10th recycled use, more than 98.4% of E. coli and S. aureus can be killed. These results indicated that 3D a-TiO2 might have utility in several promising applications such as photocatalytic water/air purification and bactericidal agents.

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