• Journal of the Korean Society of Combustion
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• v.13 no.4
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• pp.47-53
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• 2008

The reaction mechanism of methane dry reforming has been investigated using an arc-jet reactor. The effects of input power, $CO_2/CH_4$ and added $O_2$ were investigated by product analysis, including CO, $H_2$, $C_{2}H_{Y}$ and $C_{3}H_{Y}$ as well as $CH_4$ and $CO_2$. In the process, input electrical power activated the reactions between $CH_4$ and $CO_2$ significantly. The increased feed ratio of the $CO_2$ to $CH_4$ in the dry reforming does not affect to the $CH_4$ conversion. but we could observe increase in CO selectivity together with decreasing $H_2$ generation. Added oxygen can also increase not only CO selectivity but also $CH_4$ conversion. However, hydrogen selectivity was decreased significantly due to a increased $H_{2}O$ formation.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.372-381
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• 2015

The effect of preparation method on the catalytic activities of the $Ni/Al_2O_3$ catalysts on steam reforming of ethylene glycol was investigated. The catalysts were prepared with various preparation methods such as an incipient wetness impregnation, wet impregnation, and coprecipitation method. In the case of coprecipitation method, various precipitants such as KOH, $K_2CO_3$, and $NH_4OH$ were compared. The prepared catalysts were characterized by using $N_2$ physisorption, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, temperatureprogrammed reduction, pulsed $H_2$ chemisorption, temperature-programmed oxidation, scanning electron microscopy, and thermogravimetric analysis. Among the catalysts reduced at 773 K, the $Ni/Al_2O_3$ catalyst prepared by a coprecipitation with KOH or $K_2CO_3$ as precipitants showed the best catalytic performance. The preparation method affected the particle size of Ni, reducibility of nickel oxides, catalytic performance (activity and stability), and types of coke formed during the reaction. The $Ni/Al_2O_3$ catalyst prepared by a coprecipitation with KOH showed the increasing catalytic activity with an increase in the reduction temperature from 773 to 1173 K because of an increase in the reduction degree of Ni oxide species even though the particle size of Ni increased with increasing reduction temperature.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.449-453
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• 2015

Recently, surfaces with micro and nano structures are the focus of various research and engineering fields to enhance wetting characteristics of the surfaces. Hydrophilic surfaces with hierarchical structures are generally characterized by the interfacial behavior of water droplets. In this study, the interfacial behavior of water droplets is experimentally investigated considering the scale of structures. Using the dry etching and conventional lithography method, quantitative hierarchical structured surfaces are developed. The behavior of the liquid-vapor interface on the test sections is visualized using an automatic goniometer and a high-speed camera. On the basis of the visualized data, the interfacial behavior of water droplets is intensively investigated according to surface geometrical characteristics.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.4
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• pp.344-354
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• 2014

Activated charcoal supported nickel molybdenum carbide (carburized Ni-Mo/AC) catalysts were prepared by wet-impregnation followed by temperature-programmed carburization using 20% $CH_4/H_2$ gas. The effects of pH and initial Ni/Mo mole ratio during wet-impregnation step on the characteristics of the carburized Ni-Mo/AC catalysts were investigated using ICP, XRD, XPS, BET and $CO_2$-TPD techniques, and correlated with the catalytic activity of the carburized Ni-Mo/AC in methane dry reforming reaction. Comparison of the results of methane dry reforming reaction kinetics with the results of characterization of the carburized Ni-Mo/AC catalyst showed that the catalytic activity in methane dry reforming reaction was higher at higher initial Ni/Mo mole ratio or at lower pH(3~natural value). This phenomenon was related to the crystal size of metallic Ni in the carburized Ni-Mo/AC catalyst.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.263-270
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• 2009

Carbon felt surface was modified by heat or acid treatment in order to use for the electrode of a redox-flow battery. Polymers on the surface of carbon felt was removed and oxygen-containing functional group was attached after the thermal treatment of carbon felt. Thermal treatment was better for the stability of the carbon structure than the acid treatment. Oxygen-containing functional group on the thermally treated carbon felt at 500$^{\circ}C$ was confirmed by XPS and elementary analysis. BET surface area was increased from nearly zero to 96 $m^2/g$. Thermally treated carbon felt at 500$^{\circ}C$ showed lower activation polarization than the thermally treated carbon felt at 400$^{\circ}C$ and the acid-treated carbon felt in the cyclicvoltammetry and polarization experiments. The thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt was applied for the electrode to prepare vanadium redox flow battery. Voltage efficiencies of charge/discharge were 86.6%, 89.6%, and 96.9% for the thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt, respectively.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.160-165
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• 2006

A Pd-Cu-Ni alloyed hydrogen membrane has fabricated on porous nickel support formed by nickel powder. Porous nickel support made by sintering shows a strong resistance to hydrogen embrittlement and thermal fatigue. Plasma surface modification treatment is introduced as pre-treatment process instead of conventional HCl wet activation. Nickel was electroplated to a thickness of $2{\mu}m$ in order in to fill micropores at the nickel support surface. Palladium and copper were deposited at thicknesses of $4{\mu}m$ and $0.5{\mu}m$, respectively, on the nickel coated support by DC sputtering process. Subsequently, copper reflow at $700^{\circ}C$ was performed for an hour in $H_2$ ambient. And, as a result PdCu-Ni composite membrane has a pinhole-free and extremely dense microstructure, having a good adhesion to the porous nickel support and infinite hydrogen selectivity in $H_2/N_2$ mixtures.