• Journal of the Korean GEO-environmental Society
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• v.17 no.10
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• pp.5-11
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• 2016

In this study, the factors affecting commercialization of $Pt/TiO_2$ catalyst, which can oxidize HCHO at room temperature, was investigated. In order to determine the optimum noble metal loading, the catalytic activity was evaluated by varying the Pt loadings; the best catalytic activity was achieved for 1 wt% of Pt. In addition, the catalyst prepared under the reduction condition showed an excellent HCHO oxidation conversion at room temperature. Based on these results, it was confirmed that the activity could be changed by oxidation state of active metal, and in case of Pt, metallic Pt ($Pt^0$) species was more active on HCHO oxidation at room temperature. As a result of evaluating an effect of space velocity to determine the optimum operating condition, it was found that in the lower space velocity, conversion rate of HCHO was increased due to increase of catalyst bed. Catalytic activity was greater in the presence of moisture than in its absence. Through above results, the key factors for commercialization of oxidation catalyst, which was operated at room temperature even without any additional energy source was confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.626-631
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• 2019

The policy-making and technological development for the supply expansion of eco-friendly automobiles has been continuing, but the internal combustion engines still accounts for about 95%. Also, in order to meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is gradually increasing. This study is a basic study for the post-Euro-VI exhaust response of CNG buses, and it is to investigate the basic characteristics according to Pd substitution transition metal effect, catalyst volume effect and space velocity. A catalysts was prepared and tested using a model gas reactor. The NGOC catalyst with 3Pd exhibited the highest catalytic activity with 22% at $300^{\circ}C$, 48% at $350^{\circ}C$ and about 75% at $500^{\circ}C$. 3Co NGOC containing 3wt% of transition metal was excellent in oxidation ability, and it was small in size of 2nm, and the degree of catalyst dispersion was improved and de-NO/CO conversion was high. The volume of the NGOC-LNT-SCR catalyst system was optimal in the combination of 1.5+0.5+0.5 with a total score of 165, considering $de-CH_4/NOx$ performance and catalyst cost. For SV $14,000h^{-1}$, the $CH_4$ reduction performance was the highest at about 20%, while the SV $56,000h^{-1}$ was the lowest at about 5%. If the space velocity is small, the flow velocity decreases and the time remaining in the catalyst volume become long, so that the harmful gas was reduced.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.296-303
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• 2021

The objective of this study is to investigate the applicability of a Cu-supported honeycomb catalyst as a catalyst for decomposition of a low toxic liquid propellant based on ammonium dinitramide (ADN). A mixture of copper, lanthanum, and alumina was supported on the honeycomb support by wash coating to prepare a Cu-La-Al/honeycomb catalyst. We elucidated that the effect of metal loading on the physicochemical properties of Cu-La-Al/honeycomb catalyst and catalytic performance in decomposition of the ADN-based liquid propellant. As the number of wash coatings increased, the amount of active metal Cu was increased to 4.1 wt%. The BET surface area of the Cu-La-Al/honeycomb catalyst was in the range of 3.1~4.1 ㎡/g. The micropores were hardly present in Cu-La-Al/honeycomb catalysts, however, the mesopores and macropores were well developed. The Cu (2.7 wt%)-La-Al/honeycomb catalyst exhibited the highest activity in the decomposition of the ADN-based liquid propellant, which is attributed to the largest surface area, the largest pore volume, and the well-developed mesopores and macropores.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.409-416
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• 2021

Dimensionally stable electrodes are one of the important components in electrochemical water treatment processes. In the manufacturing of the dimensionally stable electrodes, the type of metal catalyst coated on the surface of the metal substrate, the coating and sintering methods substantially influence their performance and durability. In this study, using Ir-Ru-Ta ternary metal coating, various electrodes were prepared depending on the coating method under the same pre-treatment and sintering conditions, and its performance and durability were studied. As a coating method, brush and spray coating were used. As a result, the reduction in the amount of catalyst ink was achieved because more amount of metal could be coated for the electrode using spraying with the same amount of catalyst ink. In addition, the spray_2.0_3.0 electrode prepared by a specific spray coating method shows the phenomenon of cracking and the uniform coating of the ternary metal on the surface of the coating layer, and results in a high electrochemically active specific surface area, and the decomposition performance of 4-chlorophenol was superior to the other electrodes. However, it was found that there was no significant difference in durability depending on the coating method.

• Journal of the Korean Ceramic Society
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• v.41 no.12 s.271
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• pp.880-883
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• 2004

Carbon nanofibers could be selectively formed at the groove area of the MgO substrate using microwave plasma-enhanced chemical vapor deposition system. Iridium metal was used as a catalyst layer for the formation of the carbon nanofibers. The growth direction of the carbon nanofibers was vertical to the substrate surface. The selectively grown iridium-catalyzed carbon nanofibers show around $1.8V/{\mu}m$ turn-on voltage and $1.0\;mA/cm^2$ field emission current density at $2.65\;V/{\mu}m$ in the field emission measurement.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.478-481
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• 2001

The spent petrochemical catalyst used in the manufacturing process of terephthalic-acid contains valuable metals such as cobalt and manganese. To recover these metals, sulfuric acid leaching was performed with hydrogen peroxide as a reducing agent. Low extractions of Mn, Co and Fe were obtained by sulfuric acid leaching without reducing agent. With adding hydrogen peroxide as a reducing agent, the high extraction of these metals could be obtained. Different from general leaching experiment, the extraction rates of metal components were decreased with increasing reaction temperature in this case. Under the optimum condition, the extraction rates of Mn, Co and Fe were 93.0%, 87.0% and 100% respectively.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.8
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• pp.1060-1068
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• 1998

The effects of various catalysts and softners on the anti-crease finish of ramie with glyoxal were investigated. A number of metal salts commonly used as Lewis acid catalysts in DP finishing of cotton with formaldehyde and N-methylol agents were screened for glyoxal treatment of ramie fabric. Various organic and inorganic acids were mixed with Lewis acid catalyst as co-catalysts to improve catalytic activity. As a result, the combination of aluminum sulfate and citric acid was proven highly effective in catalyzing the crosslinking of ramie cellulose by glyoxal under lower curing temperature. With a mixed catalyst, performance properties, such as whiteness and tearing strength as well as wrinkle recovery of treated ramie fabric were improved as compared with that treated with aluminum sulfate alone. Additional improvement of tearing strength and wrinkle recovery was achieved by applying silicons softner in the treatment bath.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.57-72
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• 1990

The oxidation of carbon monoxide on a catalyst, $LaSrNiCoO_3$ was investigatigated with a plug flow system. Kinetic quantities such as reaction-rate, reaction order and Arhenius-parameters at various reactor temperature from 200$^\circ$C to 300$^\circ$C were determined. Also, the optimum condition for the oxidation of carbon monoxide with this catalyst was determined and are as follows. Partial pressure of oxigen ; 428mmHg Partial pressure of carbon monoxide ; 332mmHg Mixed moral ratio of oxigen and Carbon monoxide ; 1.3 : 1 Total gas flow ; 224ml/min Reaction temperature ; 340$^\circ$C The reaction kinetic equation at the optimum condition, temperature range from 200$^\circ$C to 340$^\circ$C, are as follow. $$ $v = Ae^{6.5Kcal/RT} [CO]^{0.93 \sim 0.98} [O_2]^{0.42 \sim 0.50}$ $$ In addition to this, numerical calculation were performed to evaluate the mass and heat transfer effect on this system.

• Ceramist
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• v.22 no.2
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• pp.189-197
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• 2019

Direct methanol fuel cells (DMFCs) have found a wide variety of commercial applications such as portable computer and mobile phone. In a fuel cell, the catalysts have an important role and durability and efficiency are determined by the ability of the catalyst. The activity of the catalyst is determined by the structure and shape control of the nanoparticles and the dispersion of the nanoparticles and application system. The surface energy of nanoparticles determines the activity by shape control and the nanostructure is determined by the ratio of bi- and tri-metals in the alloy and core-shell. The dispersion of nanoparticles depends on the type of support such as carbon, graphen and metal oxide. In addition, a hybrid system using both optical and electrochemical device has been developed recently.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.31-37
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• 2013

To acquire enhanced adsorption capacity for especially targeted VOCs, activated carbon fiber of which surface area was $1,100m^2/g$ was selected and active metals were loaded. After screening study, Cr and Cu were selected as a base metal for improving adsorption capacity of activated carbon fiber. For acquiring better performance, metal loading, loading temperature, loading hours and kinds of loaded metals were changed as preparing variables. Properties measurement and adsorption capacity evaluation were performed. We found that the best conditions for metal loading were 5 hours loading at $100^{\circ}C$ and the adsorption capacity was enhanced almost double. Also we confirmed that more than 0.5 seconds contact time is needed for best adsorbate diffusion and adsorption over activated carbon fiber.