• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.508-512
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• 2017

In this study, we carried out the study on the combustion characteristics of HTPB/AP propellants with Al and Zr as fuel metal in order to develop the solid propellant with high burning rate. The major combustion characteristics of propellant were investigated as measuring of the burning rate and pressure exponent, and the HTPB/AP solid propellants were prepared with introducing Butacene as burning rate catalyst for the enhancement of burning rate. The propellant with Al and Zr was demonstrated the improvement of propellant performance and combustion characteristic.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2311-2315
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• 2011

Alumina supported polyphosphoric acid (PPA/$Al_2O_3$) was successfully prepared by impregnation of alumina support by polyphosphoric acid and characterized using FT-IR spectroscopy, the $N_2$ adsorption/desorption analysis (BET), thermal analysis (TG/DTG), and X-ray diffraction (XRD) techniques. The catalytic behavior of this new solid acid supported heterogeneous catalyst was checked in the synthesis of 14-aryl-14H-dibenzo[a, j]xanthenes by cyclocondensation reaction of ${\beta}$-naphthol and aryl aldehydes under solvent-free conditions. The results showed that the novel catalyst has high activity and the desired products were obtained in very short reaction times with high yields. Moreover, the catalyst can be easily recovered by filtration and reused at least three times with only slight reduction in its catalytic activity.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.328.2-328.2
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• 2014

Semiconductor nanowires (NWs) have attracted research interests due to the distinct physical properties that can lead to variousoptical and electrical applications. In this paper, we have grown InAs NWs viagold (Au)-assisted vapor-liquid-solid (VLS) and catalyst-free vapor-solid (VS) mechanisms and investigated on the p-type doping profile of the NWs. Metal-organic chemical vapor deposition (MOCVD) is used for the growth of the NWs. Trimethylindium (TMIn) and arsine (AsH3) were used for the precursor and diethyl zinc (DEZn) was used for the p-type doping source of the NWs. The effectiveness of p-type doping was confirmed by electrical measurement, showing an increase of the electron density with the DEZn flow. The structural properties of the InAs NWs were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, we characterize atomic distribution of InAs NWs using energy-dispersive X-ray spectroscopy (EDX) analysis.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.112-113
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• 2014

The submicron-rods of $Cu_2O$ with diameters of 100-700 nm and lengths of $2-8{\mu}m$ were synthesized by radio frequency magnetron sputtering. The abundance of Cu species, which is modulated by the $Ar/O_2$ ratio during the sputtering process affect directly to the growths of the $Cu_2O$ branches on the bodies of the submicron-rods. Transmission electron microscopy and elemental mapping reveal that metallic Cu are existed on the heads of the $Cu_2O$ rods. The growth rate, catalyst phase and shape reveal that vapor-quasiliquid-solid was the growth mechanism of the formations of those structures.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.3
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• pp.270-275
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• 2016

A simple solid state incorporation method was employed in order to incorporate Pd nanocatalyst into a Nafion film for polymer electrolyte membrane fuel cell (PEMFC) via the reduction of palladium (II) bis (acetylacetonate), $Pd(acac)_2$. It was sublimed, penetrated into Nafion film and then reduced to Pd nanoparticles simultaneously in a glass reactor of N2 atmosphere at $180^{\circ}C$ for 1, 3 and 5 min. This reaction was took place without any reducing agent and any solvent. The morphology of the Pd nanoparticles was observed by transmission electron microscopy (TEM), and Pd distribution was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). And 23% modification of tensile strength of Pd/Nafion composite film was measured by universal testing machine and I-V curve was estimated by using a unit cell with $5{\times}5cm^2$ active area.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.821-829
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• 2006

A series of catalysts, $NiO/La_2O_3-ZrO_2/WO_3$, for acid catalysis was prepared by the precipitation and impregnation methods. For the $NiO/La_2O_3-ZrO_2/WO_3$ samples, no diffraction lines of nickel oxide were observed, indicating good dispersion of nickel oxide on the catalyst surface. The catalyst was amorphous to X-ray diffraction up to 300 ${^{\circ}C}$ of calcination temperature, but the tetragonal phase of $ZrO_2$ and monoclinic phase of $WO_3$ by the calcination temperatures from 400 ${^{\circ}C}$ to 700 ${^{\circ}C}$ were observed. The role of $La_2O_3$ in the catalyst was to form a thermally stable solid solution with zirconia and consequently to give high surface area and acidity. The high acid strength and high acidity were responsible for the W=O bond nature of complex formed by the modification of $ZrO_2$ with $WO_3$. For 2-propanol dehydration the catalyst calcined at 400 ${^{\circ}C}$ exhibited the highest catalytic activity, while for cumene dealkylation the catalyst calcined at 600 ${^{\circ}C}$ showed the highest catalytic activity. 25-$NiO/5-La_2O_3-ZrO_2/15-WO_3$ exhibited maximum catalytic activities for two reactions due to the effects of $WO_3$ modifying and $La_2O_3$ doping.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.155-160
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• 2011

Dimethyl ether draws an attention as a green fuel in recent years. In this study, we investigated dehydration of methanol to produce DME using solid-acid catalysts, a series of zeolite. We found that ceria took a role of promoting the reaction conversion as well as selectivity of DME formation as a cocatalyst to the zeolite catalyst. We varied Si/Al ratio and ceria percentage on the surface of the catalyst to get high performance catalyst. ZSM5-30 with 5 wt% ceria on the surface was found to have excellent DME selectivity and to be little influenced by water content in methanol feed. We proposed a reaction model and obtained kinetic parameters for the DME formation using the catalyst based on experimental results using a microreactor.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.68-71
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• 2006

Free fatty acids are not esterified by alkaline catalyst transesterification. They are detrimental to the quality specifications in biodiesel. Therefore, we tried to find solid catalyst to remove free fatty acids in feedstock. Amberlyst 15 resin was selected as the best catalyst, and the moisture content containing in the resin was found to be important for the reaction. The removal efficiency of free fatty acids was gradually decreased from 97% to 70% by ten times reuse of resin. In the transesterificaion reaction by KOH catalyst, soap formation could be decreased by 58.3% using the feedstock pretreated by resin. Consequently, the purity of biodiesel was enhanced about 10%, as compared with the non-treated feedstock.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.644-650
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• 2021

This study characterized the reforming of methane with carbon dioxide, which is a major cause of global warming. The methane decomposition reaction with carbon dioxide was carried out using transition metal catalysts. The reactivity of tin was lower than that of a transition metal, such as nickel and iron. Most of the decomposition reaction occurred in the solid state. The melting point of tin is 505.03 K. Tin reacts in a liquid phase at the reaction temperature and has the advantage of separating carbon produced by the decomposition of methane from the liquid tin catalyst. Therefore, deactivation due to the deposition of carbon in the liquid tin can be prevented. Methane decomposition with carbon dioxide produced carbon monoxide and hydrogen. Ni was used to promote the catalyst performance and enhance the activity of the catalyst and lifetime. In this study, catalysts were synthesized using the excess wet impregnation method. The effect of the reaction temperature, space velocity was measured to calculate the activity of catalysts, such as the activation energy and regeneration of catalysts. The carbon-deposited tin catalyst regeneration temperature was 1023 K. The reactivity was improved using a nickel co-catalyst and a water supply.

• Journal of the Korean Applied Science and Technology
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• v.20 no.3
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• pp.230-236
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• 2003

Synthesis gas is commercially produced by a steam reforming process. However, the process is highly endothermic and energy-consuming. Thus, this study was conducted to produce synthesis gas by the partial oxidation of methane to decrease the energy cost. Supported Ni catalysts were prepared by the impregnation method. To examine the activity of the catalysts, a differential fixed bed reactor was used, and the reaction was carried out at $750{\sim}850^{\circ}C$ and 1 atm. The fresh and used catalysts were characterized by XRD, XPS, TGA and AAS. The highest catalytic activity was obtained with the 13wt% Ni/MgO catalyst, with which methane conversion was 81%, and $H_2$ and CO selectivities were 94% and 93%, respectively. 13wt% Ni/MgO catalyst showed the best $MgNiO_2$ solid solution state, which can explain the highest catalytic activity of the 13wt% Ni/MgO catalyst.