• Korean Journal of Materials Research
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• v.14 no.7
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• pp.500-504
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• 2004

It is well-known that adjacent Pd-MILC enhanced the rate of Ni-MILC. And the phenomena can be explained by tensile stress propagation between amorphous silicon and Pd silicide which is catalyst of crystallization. In this study, we modified tensile stress by changing geometry of amorphous silicon to prove that there is a direct relation between tensile stress and Ni-MILC rate enhancement. When the tensile stress concentrated, the Ni-MILC rate was enhanced more(14.5 ${\mu}m/hr$) by Pd-MILC while the conventional Pd-MILC enhanced Ni-MILC rate was 11 ${\mu}m/hr$. As the result we can be sure that the tensile stress causes the enhancement of Ni-MILC rate.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.4
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• pp.179-188
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• 2000

The anodic reaction of hydrogen/oxygen gas mixture at platinum or palladium electrode interfacing with a solid polymer electrolyte was investigated using AC impedance method. The impedance spectrum of the electrode reactions of the mixture depends on the gas composition, electrode roughness, the mode of electrochemical operation and the cell potential. For electrolysis mode of operation, the spectrum taken for the reaction on a rough platinum electrode for the gas mixture revealed clearly that the local anodic reduction of oxygen gas takes place concurrently with the anodic oxidation of hydrogen gas.

• Bulletin of the Korean Chemical Society
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• v.18 no.12
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• pp.1269-1273
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• 1997

The system which employs iron, palladium, molecular oxygen and hydrogen as a model mono-oxygenase, has been investigated to develop a new method for selective cyclohexane oxidation uner mild conditions. This system provides much higher yield and selectivity for the formation of cyclohexanol and cyclohexanone compared to that of the existing industrial method. When the catalytic system, FeCl2-Pd/alumina, was employed, the oxidation system required acetone as a solvent to be efficient and acidifying the solvent by a little addition of acetic acid or HCl made the system more efficient. The Pd catalyst was recyclable without a significant deactivation but the recycling of ferrous chloride showed the decrease in the activity. On the other hand, the heterogeneous catalytic system, Pd/Fe2O3 could be recovered easily and reused after drying treatment.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.4
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• pp.277-285
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• 2001

We developed a compact, 10 kWe, purifier-integrated reformer which supplies hydrogen for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by palladium alloy membrane and catalytic combustion by noble metal coated wire-mesh catalyst were combined with the conventional methanol steam reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems. In this system, steam reforming, hydrogen purification, and catalytic combustion take place all in a single reactor so that the whole system is compact and easy to operate. The module produces $8.2Nm^3/hr$ of 99.999% or higher purity hydrogen with CO impurity less than 10 ppm, which is equivalent to 10 kWe when PEMFC has 45 % efficiency. Thermal efficiency of the module is 81 % and the power density of the module is 1.6 L/kWe. As the results of experiments, cold-start time has been measured about 20 minutes. Response time of hydrogen production to the change of the feed rate has been within 1 minutes.

• Journal of the Korean Chemical Society
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• v.28 no.5
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• pp.335-341
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• 1984

Acetals of ${\alpha},{\beta}$-unsaturated aldehydes reacted readily with aryl bromides in the presence of palladium catalyst and triethylamine to form aryl conjugated enals. Acrolein diethyl acetal and methacrolein diethyl acetal were reacted with phenyl bromides with substituents such as methyl and isopropyl groups at $100^{\circ}C$. The reaction products yields except the reaction of o-bromotoluene with methacrolein diethyl acetal. The products were identified by proton nuclear magnetic resonance and infrared spectroscopy. In the reverse combination of reactants to prepare aliphatic 2,4-dienals in good yield of above 50%, 3-bromopropenal dimethyl acetal and (E)-3-bromo-2-methylpropenal diethyl acetal were used as vinylic halide reactants and 1-alkenes and ethyl acrylate as olefin reactants.

• Korean Journal of Materials Research
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• v.21 no.6
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• pp.309-313
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• 2011

The power capacitors used as vehicle inverters must have a small size, high capacitance, high voltage, fast response and wide operating temperature. Our thin film capacitor was fabricated by alumina layers as a dielectric material and a metal electrode instead of a liquid electrolyte in an aluminum electrolytic capacitor. We analyzed the micro structures and the electrical properties of the thin film capacitors fabricated by nano-channel alumina and metal electrodes. The metal electrode was filled into the alumina nano-channel by electroless nickel plating with polyethylene glycol and a palladium catalyst. The spherical metals were formed inside the alumina nano pores. The breakdown voltage and leakage current increased by the chemical reaction of the alumina layer and $PdCl_2$ solution. The thickness of the electroless plated nickel layer was 300 nm. We observed the nano pores in the interface between the alumina layer and the metal electrode. The alumina capacitors with nickel electrodes had a capacitance density of 100 $nF/cm^2$, dielectric loss of 0.01, breakdown voltage of 0.7MV/cm and leakage current of $10^4{\mu}A$.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.404-409
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• 2006

The catalytic combustion of toluene over Pd-Cu/USY zeolite has been examined by using FT-IR spectroscopy in a closed system under dry and humid conditions. The catalytic combustion of toluene (700 ppmv) in the temperature range of $80-220^{\circ}C$ has been investigated by using a fixed bed reactor. The Pd-Cu/USY catalyst showed the highest catalytic performance with respects to the PdO-CuO/USY and Pd/USY. Comparing to $PdO/Al_2O_3$ catalysts, the slight improvement in conversion was observed over PdO/USY catalysts under humid condition since USY zeolite is hydrophobic substrate and water give an additional oxygen source to zeolite surface like oxygen. The reduced catalysts showed more enhanced catalytic activity due to the reduced activation energy of combustion of toluene than oxidized catalysts such as PdO/USY and PdO-CuO/USY.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.119-124
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• 2018

The production of methyl N-phenyl carbamate by an oxidative carbonylation method of aniline and methanol is of great interest as an environmentally friendly process that can replace the monomer production process of a polymer produce using conventional phosgene. In this study, heterogeneous catalysts were prepared by using Y-zeolite, $SiO_2$, $Al_2O_3$ as support, and oxidative carbonylation continuous operation from aniline and methanol was attempted using the prepared heterogeneous catalyst. Batch reactor was used to determine the support, and various reaction conditions such as reaction temperature, reaction pressure, and effect of promoter were established using palladium catalyst. A reaction kinetics study was conducted under optimum reaction conditions. The basic data for carbamate process development were obtained by performing continuous operation for a long time under established reaction condition.

• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.1-9
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• 2016

Combined removal of n-heptane and carbon monoxide (CO) using a plasma-catalytic process was investigated. The performance of the plasma-catalytic process was compared with that of the catalyst-alone process to characterize the decomposition of n-heptane and CO with the operation parameters such as the type of catalyst, reaction temperature, and discharge power. From several sets of experiments, it was found that the decomposition efficiency of n-heptane mainly depended on the specific input energy rather than the reactor temperature, whereas the oxidation of CO on both the energy density and the reaction temperature. The results conducted over several metal oxide catalysts exhibited that the decomposition efficiency of n-heptane was in the order: $Pd/{\gamma}-Al_2O_3$ > $Ru/{\gamma}-Al_2O_3{\approx}Ag/{\gamma}-Al_2O_3$. Especially, $Pd/{\gamma}-Al_2O_3$ catalyst did hardly generate CO as a byproduct during the decomposition of n-heptane under an appropriate condition, revealing $CO_2$ selectivity of nearly 100%. The CO oxidation efficiency was largely affected by the type of catalyst ($Pd/{\gamma}-Al_2O_3$ > $Ru/{\gamma}-Al_2O_3$ > $Ag/{\gamma}-Al_2O_3$). At temperatures below $180^{\circ}C$, the plasma-catalytic process was more effective in the oxidation of CO, while above $180^{\circ}C$, the catalytic process resulted in slightly higher CO oxidation efficiency.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.121-129
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• 2017

Pd based catalysts were prepared by impregnating palladium precursor using incipient wetness method on $TiO_2$, $Al_2O_3$, $ZrO_2$, and $SiO_2$ and were applied for the selective oxidation of $H_2$ in the presence of CO. Their physicochemical properties were studied by X-ray diffraction (XRD), $N_2$-sorption, temperature programmed desorption of CO (CO-TPD) and (CO+$H_2O$)-TPD, temperature programmed reduction of CO (CO-TPR) and XPS a. The results of CO- and (CO+$H_2O$)-TPD showed the correlation between peak temperature of TPD and catalytic activities for $H_2$ and CO conversion. The $Pd/ZrO_2$ catalyst exhibited the highest conversion of $H_2$. The addition of $H_2O$ vapor promotes the conversion of $H_2$ and CO by inducing easy desorption of CO and $H_2$ in the competitive adsorption of $H_2O$, CO and $H_2$.