• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.68-68
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• 2008

There are several methods for oxide coating on metals, such as aluminum or carbon nanotubes(CNTs). Usually CVD method is introduced for various oxide coating on CNTs. Another method is electrochemical method which use potential-pH diagram for oxide coating on metal or CNTs. In this experiment, electrochemical coating parameter for oxide coating on aluminum template modified by acids and hydrogen peroxide ($H_2O_2$) were examined. SEM micrographs displayed clearly $Ni(OH)_2$ coating on template. For confirmation of electrochemical method application to EDLC electrode material fabrication, EDS spectrum was analyzed.

• Journal of the Korean Electrochemical Society
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• v.7 no.2
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• pp.100-107
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• 2004

The nano or micro sized structures of conducting polymer had been prepared by synthesizing the desired polymer within the pores of template of nano or micro porous membrane filter. In this study, we had tried to fabricate conducting polymer microstructures on an electrode by using electrochemical deposition adopting template synthesis. Our attention was focused on two different things, attaching template on the electrode and fabricating microstructures only at limited areas of the electrode. A conducting polymer, PEDiTT (poly 3,4-ethylenedithi-athiophene) solution was blended with PVA(polyvinyl alcohol) solution and used as an conducting adhesive. After attaching template membrane, the electrode were immersed in 0.5M pyrrole in 0.1M KCI solution, and electrochemical polymerization was performed. The growth process of the microstructures studied by SEM. The electrochemical fabrication of conducting polymer was performed by using two-electrode system. A large working electrode and a micro scale disc electrode were used for the confined area synthesis. Polymerization potential was 4V in an electrolytic solution made of KCI in deionized water. The optimum polymerization conditions were, i.e. (4V/100sec) for $250{\mu}m$ electrode and (6V/30 sec) for $10{\mu}m$ electrode.

• Journal of Powder Materials
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• v.19 no.5
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• pp.367-372
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• 2012

Single crystalline Cu nanowires with controlled diameters and aspect ratios have been synthesized using electrochemical deposition within confined nanochannels of a porous anodic aluminium oxide(AAO) template. The diameters of nano-sized cylindrical pores in AAO template were adjusted by controlling the anodization conditions. Cu nanowires with diameters of approximately 38, 99, 274 nm were synthesized by the electrodeposition using the AAO templates. The crystal structure, morphology and microstructure of the Cu nanowires were systematically investigated using XRD, FE-SEM, TEM and SAED. Investigation results revealed that the Cu nanowires had the controlled diameter, high aspect ratio and single crystalline nature.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2423-2430
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• 2014

Nitrogen-doped short tubular carbons (N-STCs) with big inner diameter have been successfully synthesized via carbonization of polydopamine (PDA) wrapped halloysite nanotubes (HNTs). The obtained N-STCs have average length of $0.3{\mu}m$ with big inner diameter (50 nm), thin wall (2-3 nm) and large surface area ($776m^2g^{-1}$), and show excellent electrochemical properties. As an example in electrochemical applications, N-STCs were used to electrochemically detect hydrogen peroxide ($H_2O_2$) and glucose. The results showed that the N-STCs modified glassy carbon (N-STCs/GC) electrode had much better analytical performance (lower detection limit and wider linear range) compared to the acid-treated carbon nanotubes (AO-CNTs) based GC electrode. The unique structure endows N-STCs the enhanced electrochemical performance and promising applications in electrochemical sensing.

• Journal of the Korean Electrochemical Society
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• v.17 no.2
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• pp.86-93
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• 2014

Mesoporous tin oxide (meso-$SnO_2$) with 5 nm mesopore and well-aligned $SnO_2$ nanowire-bundles with 5~7 nm diameters were prepared by template synthesis method. In addition to meso-$SnO_2$, meso-$SnO_2$/$SiO_2$, which has almost the same structure as meso-$SnO_2$ including $SiO_2$ used as the template were prepared by the modification of template synthesis. X-ray diffraction, N2 adsorption-desorption isotherms, transmission electron microscopy observed structures of meso-$SnO_2$ and meso-$SnO_2$/$SiO_2$. Although the meso-$SnO_2$/$SiO_2$ showed some positive evidences to suppress the volume change of meso-$SnO_2$ through cyclic voltammogram, electrochemical impedance spectroscopy, and voltage profiles during cycling, its cycle life was not improved highly to address modified structural effects. Thus, further study might be done to control the nanostructure of meso-$SnO_2$/$SiO_2$ for enhanced cycle performance.

• Proceedings of the Korean Magnestics Society Conference
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• 2014.11a
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• pp.55-55
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• 2014

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2279-2286
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• 2012

The template synthesis of copper(II) and nickel(II) complexes derived from 2,6-diformyl-4-methylphenol with diethylenetriamine or 1,2-bis(3-aminopropylamino)ethane produce the 12-membered $N_3O$ and 17-membered $N_4O$ macrocyclic complexes, respectively. The geometry of the complexes has been determined with the help of electronic and EPR spectroscopic values and found to be five coordinated square pyramidal and, six coordinated distorted tetragonal for 12-membered and 17-membered macrocyclic complexes, respectively. Electrochemical studies of the mononuclear $N_3O$ and $N_4O$ copper(II) complexes show one irreversible oneelectron reduction wave at $E_{pc}=-1.35$ and -1.15 V respectively, and the corresponding nickel(II) complexes show irreversible one-electron reduction wave at $E_{pc}=-1.25$ and -1.22 V, respectively. The nickel(II) complexes show irreversible one-electron oxidation wave at $E_{pa}=+0.84$ and +0.82 V, respectively. All the complexes were evaluated for in vitro antimicrobial activity against the human pathogenic bacteria and fungi.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1462-1466
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• 2013

We demonstrate that ruthenium oxide ($RuO_2$) nanotubes with controlled dimensions can be synthesized using facile electrochemical means and anodic aluminum oxide (AAO) templates. $RuO_2$ nanotubes were formed using a cyclic voltammetric deposition technique and an aqueous plating solution composed of $RuCl_3$. Linear sweep voltammetry (LSV) was used to determine the effective electrochemical oxidation potential of $Ru^{3+}$ to $RuO_2$. The length and wall thickness of $RuO_2$ nanotubes can be adjusted by varying the range and cycles of the electrochemical cyclic voltammetric potentials. Thick-walled $RuO_2$ nanotubes were obtained using a wide electrochemical potential range (-0.2~1 V). In contrast, an electrochemical deposition potential range from 0.8 to 1 V produced thin-walled and longer $RuO_2$ nanotubes in an identical number of cycles. The dependence of wall thickness and length of $RuO_2$ nanotubes on the range of cyclic voltammetric electrochemical potentials was attributed to the distinct ionic diffusion times. This significantly improves the ratio of surface area to mass of materials synthesized using AAO templates. Furthermore, this study is directive to the controlled synthesis of other metal oxide nanotubes using a similar strategy.

• Bulletin of the Korean Chemical Society
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• v.10 no.4
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• pp.362-366
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• 1989

Square planar nickel(II) and copper(II) complexes of 14-membered macrocyclic ligands containing various alkyl pendant arms at the uncoordinated nitrogen atoms, 1,8-dipropyl, 1,8-dibutyl, 1,8-bis(2-methylpropyl), 1,8-bis(2-ethylhexyl), and 1,8-dibenzyl-1,3,6,8,10,13-hexaazacyclotetradecane have been prepared from the template condensation of ethylenediamine, formaldehyde, and appropriate primary amines in the presence of the metal ion. The spectroscopic and electrochemical properties of these complexes are similar to those of tetraaza macrocyclic complexes and are not affected significantly by the nature of the alkyl groups.

• Journal of the Korean Electrochemical Society
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• v.14 no.3
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• pp.184-190
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• 2011

$LiMn_2O_4$ with mesoporous hollow sphere shape was synthesized by precipitation method with silica template. The synthesized $LiMn_2O_4$ has nanosized first particle and mesoporous hollow sphere shape. Silica template was removed by chemical etching method using NaOH solution. When the concentration of NaOH solution was increased, first particle size of manganese oxide was decrease and confirmed mesoporous hollow shpere shape. X-ray diffraction(XRD) patterns revealed that the synthesized samples has spinel structure with Fd3m space group. In case the ratio of silica and maganese salt increased, the size of first particles was decreased. The tetragoanal $LiMn_2O_4$ with micron size was synthesized at ratio of silica and manganese salt over 1 : 9. The prepared samples were assembled as cathode materials of Li-ion battery with 2032 type coin cell and their electrochemical properties are examined by charge-discharge and cyclic performance. Electrochemical measurements show that the nano-size particles had lower capacity than micron-size particles. But, cyclic performance of nano-size particles had better than that of micron-size particles.