• Clean Technology
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• v.22 no.2
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• pp.132-138
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• 2016

The emission of SO₂ is inevitable in case of combustion of most fossil fuels except LNG in commercial power plant which has a bad effect on the durability of SCR catalyst. To develop a low temperature SCR catalyst which has a high NOx removal performance and excellent durability to SO₂, V₂O₅/TiO₂ catalysts were prepared by coating on the metal foam substrate with the impregnation amount of Sb₂O₃ as promotor. This study has evaluated the NOx removal performance and the durability to SO₂ on a laboratory scale atmospheric reactor and analyzed the properties of the prepared catalysts by means of porosimeter, BET, SEM (scanning electron microscope), EDX (energy dispersive x-ray spectrometer), XPS (X-ray photoelectron spectroscopy). It was found that the surface area of catalyst increased with the impregnation amount of Sb₂O₃ and the NOx removal performance showed the highest value at the 2 wt% impregnation of Sb₂O₃. This results was considered to be due to the optimum active site on the catalyst surface. And also, Sb₂O₃ impregnated catalysts presented that NOx removal performance was maintained despite the exposure to SO₂ for 5 hours. Therefore it was confirmed that metal foam SCR catalyst for low temperature could be manufactured with the optimum control of Sb₂O₃ impregnation according to the SO₂ presence or not.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.86.2-86.2
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• 2010

In order to improve polymer electrolyte membrane fuel cell (PEMFC) durability, the durability of membrane electrode assemblies (MEA), in which the electrochemical reactions actually occur, is one of the vital issues. Many articles have dealt with catalyst layer degradation of the durability-related factors on MEAs in relation to loss of catalyst surface area caused by agglomeration, dissolution, migration, formation of metal complexes and oxides, and/or instability of the carbon support. Degradation of catalyst layer during long-term operation includes cracking or delamination of the layer which result either from change in the catalyst microstructure or loss of electronic or ionic contact with the active surface, can result in apparent activity loss in the catalyst layer. Membrane degradation of the durability-related factors on MEAs can be caused by mechanical or thermal stress resulting in formation of pinholes and tears and/or by chemical attack of hydrogen peroxide radicals formed during the electrochemical reactions. All of these effects, the mechanical damage of membrane and degradation of catalyst layers are more facilitated by uneven stress or improper MEA fabrication process. In order to improve the PEMFC durability, therefore, it is most important to minimize the uneven stress or improper MEA fabrication process in the course of the fabrication of MEA. We analyzed the effects of the MEA fabrication condition on the PEMFC durability with MEA produced using CCM (catalyst coated membrane) method. This paper also investigated the effects of MEA fabrication condition on the PEMFC durability by adding additional treatment process, hot pressing and pressing, on the MEA produced using CCM method.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.339-346
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• 2015

The synthesis of Fischer-Tropsch (FT) oil is the catalytic hydrogenation of CO to give a range of products, which can be used for the production of high-quality diesel fuel, gasoline and linear chemicals. This studied catalyst was prepared Cobalt-supported alumina and silica by the incipient wet impregnation of the nitrates of cobalt, promoter and organic solvent with supports. Cobalt catalysts were calcined at $350^{\circ}C$ before being loaded into the FT reactors. After the reduction of catalyst has been carried out under $450^{\circ}C$ for 24h, FT reaction of the catalyst has been carried out at GHSV of 4,000/hr under $200^{\circ}C$ and 20atm. From these experimental results, we have obtained the results as following; In case of $SiO_2$ catalysts, the activity of 12wt% $Cobalt-SiO_2$ synthesized by organic solvent was about 2 or 3 times higher than the activity of 12wt% $Cobalt-SiO_2$ catalyst synthesized without organic solvent. In particular, the activity of the $Cobalt-SiO_2$ catalyst prepared in the presence of an organic solvent P was two to three times higher than that of the $Cobalt-SiO_2$ catalyst prepared without the organic solvent. Effect of Cr and Cu metal as a promoter was found little. 200 h long-term activity test was performed with a $Co/SiO_2$ catalyst prepared in the presence of an organic solvent of Glyoxal solution.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.163-172
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• 2018

In this study, selective catalytic reductions (SCR) of NO commercial catalysts were used to investigate the effect of ammonia gasification from urea solution. The effects of catalytic chemical composition on the reaction temperature and space velocity were studied. $V_2O_5/TiO_2$ catalysts, which are widely used as SCR catalysts for removal of nitrogen oxides, have better ammonia formation compare to $TiO_2$ and $WO_3-V_2O_5/TiO_2$ catalysts. The $TiO_2$ catalyst not supporting the active metal was not affected by the space velocity as compared with the catalyst supporting $V_2O_5$ or $WO_3-V_2O_5$. The active metal supported catalysts decreased in the ammonia formation as the space velocity increased.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.416-423
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• 1996

Electrochemical reduction of thionyl chloride in 1.5 M $LiAlCl_4/SOCl_2$ electrolyte solution containing tetradentate Schiff base Co(II), Ni(II), Cu(II), and Mn(II) complexes has been investigated at the glassy carbon electrode. The catalyst molecules of transition metal(II) complexes were adsorbed on the electrode surface and reduced thionyl chloride resulting in a generation of oxidized catalyst molecules. There was an optimum concentration for each catalyst compound. The current density of $SOCl_2$ reduction was enhanced up to 150% at the catalyst contained electrolyte solution. The reduction currents of thionyl chloride were increased and the reduction potentials were shifted to the negative potential as scan rates became faster. The reduction of thionyl chloride was proceeded to diffusion controlled reaction.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.536-544
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• 2017

The effects of catalysts addition on the pyrolysis reaction of biomass have been studied in a thermogravimetric analyzer (TGA). The sample biomasses were Bamboo, Pine and Hinoki. The catalysts tested were K, Zn, Cu metal compounds. The pyrolysis reactions were tested in the nonisothermal condition from the room temperature to $550^{\circ}C$ at a heating rate $50^{\circ}C/min$ on the flowing of $N_2$ purge gases. Cellulose contents of Bamboo was higher than that of Pine and Hinoki. As the results, the pyrolysis reaction of volatile matter was finished near the temperature $450^{\circ}C$. The initial decomposition temperatures of the volatile matters ($T_i$) were $165^{\circ}C$ for Bamboo, $190^{\circ}C$ for Pine, and $193^{\circ}C$ for Hinoki. $T_i$ decreased with increasing the catalyst amounts in the sample biomasses. The temperature of maximum reaction rate ($T_{max}$) were $338^{\circ}C$ for Bamboo, $378^{\circ}C$ for Pine, and $377^{\circ}C$ for Hinoki. The effects of catalysts addition on the $T_{max}$ were to decreased it. The reducing effects about $T_{max}$ was the most effective for K metal compounds catalyst. The char amounts remained after pyrolysis at $550^{\circ}C$ were 26.2% for Bamboo, 20.7% for Pine, and 20.9% for Hinoki. The char amounts increased with the catalyst amounts.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.1-6
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• 1961

It is important to study hydrazine because of the development of new uses for its derivatives. The Rasching method is the only satisfactory one for synthesizing hydrazine; it involves the oxidation of ammonia by sodium hypochlorite in the presence of some such catalyst as gelatin. Calcium hypochlorite was substituted for the sodium hypochlorite particularly in this work, applying agar-agar as catalyst. The results of the experiments are as follow: 1. The yield is proportional to the mole-ratio of ammonia to available chlorine in calcium hypochlorite and about 60% is obtained when the ratio is 20. 2. Agar-agar can be used as a catalyst and its proper concentration in the solution is 0.005%. 3. Proper concentration of available chlorine in the reaction solution is 0.23 mole/l. 4. The most effective condition for the reaction is a temperature of $60{\sim}65^{\circ}C.$ maintained for $20{\sim}25min$. 5. The reaction takes place equally well in either an open or closed container. 6. When calcium hypochlorite is applied in place of sodium hypochlorite, the yield of hydrazine is increased as much as 17%. 7. The yield of hydrazine is decreased by eliminating the suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite. 8. When $Ca(OH)_2$ is added to Rasching process, the yield of hydrazine is raised normally. 9. The fact that some metal ions, such as $Cu^{++},$ inhibit the formation of hydrazine was proved. 10. The suspension of $Ca(OH)_2$ acted as a remarkable adsorbent for $Cu^{++}$ like gelatin. The suspension of $Ca(OH)_2$ which results from the use of calcium hypochlorite acts as a catalyst, absorbing metal ions, to increase the yield of hydrazine. So I think that calcium hypochlorite is a more efficient oxidant than sodium hypochlorite in hydrazine syntheses.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.200-207
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• 2020

In this study, the effect of calcination temperature on the production of RuTi catalyst in NH₃-SCO (selective catalytic oxidation) was investigated. The RuTi catalyst was prepared using the wet impregnation method, and calcined at 400~600 ℃ for 4 h in air condition. The catalysts were named RuTi x00 where x00 means the calcination temperature. According to XRD (X-Ray diffraction), TEM (transmission electron microscope), H₂-TPR (H₂-temperature programmed reduction) analyses, RuTi x00 catalysts displayed that the dispersion of active metal decreased via increasing the calcination temperature. The catalysts with low dispersion showed a decrease in the surface adsorption oxygen species (O_β) and NH₃ adsorption amount via XPS, and NH₃-TPD analyses. Therefore, the RuTi 400 catalyst was well dispersed in the active metal on TiO₂ surface, and also, the NH₃ removal efficiency was excellent.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.134-139
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• 2024

In the steam reforming of methane reactions, the effect of adding noble metals Ru and Pd to a Ni-based catalyst as promoters was analyzed in terms of catalytic activity and hydrogen production. The synthesized catalysts were coated on the surface of a honeycomb-structured metal monolith to perform steam methane reforming reactions. The catalysts were characterized by XRD, TPR, and SEM, and after the reforming reaction, the gas composition was analyzed by GC to measure methane conversion, hydrogen yield, and CO selectivity. The addition of 0.5 wt% Ru improved the reduction properties of the Ni catalyst and exhibited enhanced catalytic activity with a methane conversion of 99.91%. In addition, reaction characteristics were analyzed according to various process conditions. Methane conversion of over 90% and hydrogen yield of more than 3.3 were achieved at a reaction temperature of 800 ℃, a gas hourly space velocity (GHSV) of less than 10000 h^-1, and a ratio of H₂O to CH₄ (S/C) higher than 3.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.75-87
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• 1994

The metal complexes containing amino acidic ligands were prepared by using 11 kinds of amino acids as ligands and Ni, Cu, Co, Zn, Fe as a central metal. The starting was continued for 4hrs at room temperature. But Bis(D,L-Serine)Ni (II), and (D,L-Serine)Co (II) were prepared by heating method($80^{\circ}C$). In order to investigated reaction activity of Bis(D,L-Aspartato) Metal(II), stirring time was varied and Bis(D,L-Tyrosine ) Metal(II) used different divalent metal salts. We anticipate getting a great value from these prepared complexes as a monomer and a catalyst of polymerization which has peculier characteristics.