• Composites Research
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• v.29 no.4
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• pp.132-137
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• 2016

Based on mussel-inspired polydopamine (PDA), a novel technique to fabricate carbon nanowire (CNW) arrays is presented for a possible use of porous carbon electrode in electrochemical energy storage applications. PDA can give more porosity and nitrogen-doping effect to carbon electrodes, since it has high graphitic carbon yield characteristic and rich amine functionalities. Using such outstanding properties, the applicability of PDA for electrochemical energy storage devices was investigated. To achieve this, the decoration of the CNW arrays on carbon fiber surface was performed to increase the surface area for storage of electrical charge and the chemical active sites. Here, zinc oxide (ZnO) nanowire (NW) arrays were hydrothermally grown on the carbon fiber surface and then, PDA was coated on ZnO NWs. Finally, high temperature annealing was performed to carbonize PDA coating layers. For higher energy density, manganese oxide ($MnO_x$) nanoparticles (NPs), were deposited on the carbonized PDA NW arrays. The enlarged surface area induced by carbon nanowire arrays led to a 4.7-fold enhancement in areal capacitance compared to that of bare carbon fibers. The capacitance of nanowire-decorated electrodes reached up to $105.7mF/cm^2$, which is 59 times higher than that of pristine carbon fibers.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.540-544
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• 2015

A bath for electrodeposition of platinum nanoparitcles on low-cost graphite substrates was developed to attach nanoparticles directly onto a substrate, and electrochemical characteristics of the electrodeposition of platinum nanoparticles were investigated. The reaction mechanism was examined by the analysis of polarization behavior. Cyclic voltammetry measurements revealed that the elecrodeposition of platinum nanoparticles was limited by mass transfer. The chronoamperometric study showed an instantaneous nucleation mechanism during the electrodeposition of platinum nanoparticles on graphite. Because graphite is much cheaper than other carbon-based substrates, the electrodeposition of platinum nanoparticles on the graphite is expected to have useful applications.

• Journal of Adhesion and Interface
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• v.18 no.2
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• pp.75-81
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• 2017

In this study, we synthesized mesoporous carbon (Carbonized Ni-FDU-15) containing nanoporous structures and magnetic nanoparticles. Carbonized Ni-FDU-15 was synthesized via evaporation-induced self-assembly (EISA) and direct carbonization by using a triblock copolymer (F127) as a structure-directing agent, a resol precursor as a carbon-pore wall forming material, and nickel (II) nitrate as a metal ion source. The mesoporous carbon has a well-ordered two-dimensional hexagonal structure. Meanwhile, nickel (Ni) metal and nickel oxide (NiO) were produced in the magnetic nanoparticles in the pore wall. The size of the nanoparticles was about 37 nm. The surface area, pore size and pore volume of Carbonized Ni-FDU-15 were $558m^2g^{-1}$, $22.5{\AA}$ and $0.5cm^3g^{-1}$, respectively. Carbonized Ni-FDU-15 was found to move in the direction of magnetic force when magnetic force was externally applied. The magnetic nanoparticle-bearing mesoporous carbons are expected to have high applicability in a wide variety of applications such as adsorption/separation, magnetic storage media, ferrofluid, magnetic resonance imaging (MRI) and drug targeting, etc.

• Journal of the Korean Ceramic Society
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• v.52 no.4
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• pp.284-289
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• 2015

This study examined carbon layer coating on silicon carbide (SiC) fibers by utilizing solid-state and wet chemistry routes to confer toughness to the fiber-reinforced ceramic matrix composites, as an alternative to the conventional pyrolytic carbon (PyC) interphase layer. Electrophoretic deposition (EPD) of carbon black nanoparticles using both AC and DC current sources, and the vacuum infiltration of phenolic resin followed by pyrolysis were tested. Because of the use of a liquid phase, the vacuum infiltration resulted in more uniform and denser carbon coating than the EPD routes with solid carbon black particles. Thereafter, vacuum infiltration with controlled variation in phenolic resin concentration, as well as the iterations of infiltration steps, was improvised to produce a homogeneous carbon coating having a thickness of several hundred nanometers on the SiC fiber. Conclusively, it was demonstrated that the carbon coating on the SiC fiber could be achieved using a simpler method than the conventional chemical vapor deposition technique.

• Carbon letters
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• v.16 no.1
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• pp.1-10
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• 2015

In recent years, flame synthesis has absorbed a great deal of attention as a combustion method for the production of metal oxide nanoparticles, carbon nanotubes, and other related carbon nanostructures, over the existing conventional methods. Flame synthesis is an energy-efficient, scalable, cost-effective, rapid and continuous process, where flame provides the necessary chemical species for the nucleation of carbon structures (feed stock or precursor) and the energy for the production of carbon nanostructures. The production yield can be optimized by altering various parameters such as fuel profile, equivalence ratio, catalyst chemistry and structure, burner configuration and residence time. In the present report, diffusion and premixed flame synthesis methods are reviewed to develop a better understanding of factors affecting the morphology, positioning, purity, uniformity and scalability for the development of carbon nanotubes along with their correlated carbonaceous derivative nanostructures.

• Proceedings of the Korean Vacuum Society Conference
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• 2005.02a
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• pp.136-136
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.297-297
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• 2005

• 한국전자현미경학회:학술대회논문집
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• 2004.11a
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• pp.89-94
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• 2004

• Journal of Hydrogen and New Energy
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• v.31 no.5
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• pp.419-428
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• 2020

The kinetics of direct methanation over activated charcoal-supported molybdenum catalyst at 30 bar was studied in a cylindrical fixed-bed reactor. When the temperature was not higher than 400℃, the CO conversion increased with increasing temperature according to the Arrhenius law of reaction kinetics. While XRD and Raman analysis showed that Mo was present as Mo oxides after reduction or methanation, TEM and XPS analysis showed that Mo₂C was formed after methanation depending on the loading of Mo precursor. When the temperature was as high as 500℃, the CO conversion was dependent not only on the Arrhenius law but also on the catalyzed reaction by nanoparticles, which came off from the reactor and thermocouple by metal dusting. These nanoparticles were made of Ni, Fe, Cr and alloy, and attributed to the formation of carbon deposit on the wall of the reactor and on the surface of the thermocouple. The carbon deposit consisted of amorphous and disordered carbon filaments.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1025-1028
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• 2008

With the assistance of thermal pyrolysis process for hydrocarbon gases, the formation and growth of particulate carbon was systematically investigated as a function of temperature in the gas phase. The yield and average size of pyrocarbon particles were found to increase with increasing pyrolysis temperature. The difference in the yield of carbon particles generated by pyrolizing acetylene and ethylene gas posed a question about the role of hydrogen in the pyrolysis of hydrocarbon gases. In order to reveal the role of hydrogen, controlled amount of hydrogen was added to the acetylene pyrolysis, and then hydrogen addition was observed to suppress the formation and growth of carbon particles. One can control the size of pyrocarbon particles by controlling the hydrogen gas addition.