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Dive into the research topics where A-Ra Ko is active.

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Featured researches published by A-Ra Ko.


RSC Advances | 2012

Octahedral Pt-Pd alloy catalysts with enhanced oxygen reduction activity and stability in proton exchange membrane fuel cells

Young-Woo Lee; A-Ra Ko; Do-Young Kim; Sang-Beom Han; Kyung-Won Park

Structure-controlled Pt-based catalysts have been known to exhibit improved electrocatalytic activities due to particularly modulated surface structures favorable for hydrogen oxidation or oxygen reduction reactions. We prepare octahedral Pt-Pd alloy nanoparticles such as Pt3Pd1, Pt1Pd1, Pt1Pd3 by reducing metal ions with glycerol as a reducing agent in an aqueous solution. The octahedral Pt-Pd nanoparticles are well-defined alloy nanostructures with dominant {111} facets. Among them, the octahedral Pt3Pd1 shows excellent electrochemical properties i.e., much enhanced electrocatalytic activity and stability for oxygen reduction reactions in comparison with conventional Pt-based catalysts.


Catalysis Science & Technology | 2011

3-Dimensional TiO2 nanostructure supports and their improved electrochemical properties in methanol electrooxidation

Jae-Kyung Oh; Young-Woo Lee; Sang-Beom Han; A-Ra Ko; Do-Young Kim; Hyun-Su Kim; Si-Jin Kim; Bumwook Roh; Inchul Hwang; Kyung-Won Park

The TiO2 nanostructure support consists of backbones and branches of a rutile phase forming a 3-dimensional structure with high specific surface area. The Pt catalysts on the TiO2 nanostructure supports exhibit much improved electrocatalytic activity and stability toward methanol electrooxidation in comparison with conventional Pt/C.


Journal of The Korean Chemical Society | 2012

TiO 2 @carbon Core-Shell Nanostructure Electrodes for Improved Electrochemical Properties in Alkaline Solution

Do-Young Kim; Young-Woo Lee; Sang-Beom Han; A-Ra Ko; Hyun-Su Kim; Si-Jin Kim; Sang-Eun Oh; Kyung-Won Park

We report nanostructure electrodes with as a core and carbon as a shell (@C) for oxygen reduction in alkaline solution. The structure of core-shell electrodes is characterized by transmission electron microscopy, Raman spectroscopy, X-ray diffraction method, and X-ray photoelectron microscopy. The electrochemical properties of the @C electrodes are characterized using a potentiostat and compared with those of carbon supported Pt catalyst. In particular, the core-shell electrode with dominant pyridinic-N component exhibits an imporved electrocatalytic activity for oxygen reduction reaction in alkaline solution.


Physical Chemistry Chemical Physics | 2011

Synthesis of octahedral Pt–Pd alloy nanoparticles for improved catalytic activity and stability in methanol electrooxidation

Young-Woo Lee; A-Ra Ko; Sang-Beom Han; Hyun-Su Kim; Kyung-Won Park


Carbon | 2010

TiO2@carbon core–shell nanostructure supports for platinum and their use for methanol electrooxidation

Jong-Min Lee; Sang-Beom Han; Jy-Yeon Kim; Young-Woo Lee; A-Ra Ko; Bumwook Roh; Inchul Hwang; Kyung-Won Park


Journal of the American Ceramic Society | 2013

Single-Crystalline Mesoporous Molybdenum Nitride Nanowires with Improved Electrochemical Properties

Kyung-Hoon Lee; Young-Woo Lee; A-Ra Ko; Guozhong Cao; Kyung-Won Park


Materials Letters | 2011

Characterizations of tungsten carbide as a non-Pt counter electrode in dye-sensitized solar cells

A-Ra Ko; Jae-Kyung Oh; Young-Woo Lee; Sang-Beom Han; Kyung-Won Park


Chemical Communications | 2010

Cuboctahedral Pd nanoparticles on WC for enhanced methanol electrooxidation in alkaline solution

Young-Woo Lee; A-Ra Ko; Sang-Beom Han; Hyun-Su Kim; Do-Young Kim; Si-Jin Kim; Kyung-Won Park


Physical Chemistry Chemical Physics | 2011

Template-free synthesis and characterization of mesoporous tungsten nitride nanoplates

A-Ra Ko; Sang-Beom Han; Young-Woo Lee; Kyung-Won Park


Catalysis Communications | 2011

Glycerol-mediated synthesis of Pd nanostructures with dominant {111} facets for enhanced electrocatalytic activity

Young-Woo Lee; Sang-Beom Han; A-Ra Ko; Hyun-Su Kim; Kyung-Won Park

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Young-Woo Lee

Korea National University of Transportation

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Kyung-Won Park

Pennsylvania State University

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Kyung-Won Park

Pennsylvania State University

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