• Title, Summary, Keyword: metal catalyst

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Development of Oxidation Catalyst for Diesel Engine (디젤엔진 배기가스 정화용 산화촉매 개발)

  • 최경일;최용택;유관식
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.5
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    • pp.529-537
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    • 2000
  • Several Pt-based oxidation catalysts with different loading were prepared with various metal precursor solutions and characterized with H$_2$ chemisorption and TEM for Pt particle size. V was added to Pt-based catalyst for inhibiting SO$_2$oxidation reaction, as result, Pt-V/Ti-Si catalyst prepared by ERMS(Free Reduced Metal in Solution) method showed high enough activity and better inhibition on SO$_2$oxidation than Pt only catalyst. Optimum Pt particle size for diesel oxidation reaction turned out to be the size of around 20 nm. A prototype catalyst was prepared for light=duty diesel passenger car, and teated for the emission reduction performance with Korean regulation test mode(CVS-75 mode) on chassis dynamometer. The catalyst shows the performance reduction of 75~94% for CO, 53~67% for HC and 10~31% for PM. In the case of heavy-duty diesel catalyst, the domestic formal regulation teat mode D-13 was adopted for both Na engine and Turbo engine. The conversions of CO and THC are high enough(86% and 41%) while the reductions of NOx and PM are relatively low(3~11%).

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Effects of Base Metal on the Partial Oxidation of Methane Reaction (메탄의 부분산화반응에 미치는 Base metal의 영향)

  • 오영삼;장보혁;백영순;이재의;목영일
    • Journal of Energy Engineering
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    • v.8 no.2
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    • pp.256-264
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    • 1999
  • The performance of the Pt-B/cordierite catalysts (2 wt%) Pt, 70 wt% Alumina, 28 wt%) Ceria and Zirconia, B: base metal) loaded with 6∼12 wt% Mn, Cu, V, Co, Cr and Ba, respectively was studied for partial oxidation of methane reaction and compared with that of Ni loaded catalyst. As a results, it was found that Ba, Co, Cr as well as Ni loaded catalysts showed higher activity for methane partial oxidation of methane than the Mn, Cu and V loaded catalyst. But it was known that catalysts having good activity for methane showed the good activity for coke formation, too. A XRD analysis of the catalyst before and after the reaction using 5 wt% Ni/Al$_2$O$_3$) showed that there were three Ni phases. In these results, it was found that methane oxidation reaction occulted at the front of the catalyst bed consisted of NiAl$_2$O$_4$and NiO and reforming reaction occurred at the rear part of the catalyst bed consisted of reduced Ni.

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Effect of Triethylaluminum/Transition-Metal Ratio on the Physical Properties and Chemical Composition Distributions of Ethylene-Hexene Copolymers Produced by a $rac-Et(Ind)_2ZrCl_2/TiCl_4/MAO/SMB$ Catalyst

  • Park, Hai-Woong;La, Kyung-Won;Song, In-Kyu;Chung, Jin-Suk
    • Macromolecular Research
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    • v.15 no.3
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    • pp.221-224
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    • 2007
  • A silica-magnesium bisupport (SMB) was prepared by a sol-gel method for use as a support for a metal-locene/Ziegler-Natta hybrid catalyst. The prepared $rac-Et(Ind)_2ZrCl_2/TiCl_4$/MAO(methylaluminoxane)/SMB catalyst was applied to the copolymerization of ethylene with l-hexene using a variable triethylaluminum (TEA)/transition-metal (Ti) ratio and fixed MAO/transition-metal (Zr) ratio. The effect of the Al(TEA)/Ti ratio on the physical properties and chemical composition distributions (CCDs) of the ethylene-hexene copolymers produced by the hybrid catalyst was investigated. In the ethylene-hexene copolymers, two melting temperatures attributed to the metal-locene and Ziegler-Natta catalysts were clearly observed. The number of CCD peaks was increased from six to seven and the temperature region in which the peaks for the short chain branches of the ethylene-hexene copolymer were distributed became lower as the Al(TEA)/Ti ratio was increased from 300 to 400. Furthermore, the temperature regions corresponding to the lamellas in the copolymer became lower and those corresponding to the small lamellas in the copolymer became higher as the Al(TEA)/Ti ratio was increased from 300 to 400. In the copolymer produced with Al(TEA)/Ti = 500, however, only four CCD peaks were observed and the short chain branches were poorly distributed.

Low-Temperature Thermal Decomposition of Industrial N-Hexane and Benzene Vapors (산업 발생 노르말헥산과 벤젠 증기의 저온 분해)

  • Jo Wan-Kuen;Lee Joon-Yeob;Kang Jung-Hwan;Shin Seung-Ho;Kwon Ki-Dong;Kim Mo-Geun
    • Journal of Environmental Science International
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    • v.15 no.7
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    • pp.635-642
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    • 2006
  • Present study evaluated the low-temperature destruction of n-hexane and benzene using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst. The parameters tested for the evaluation of catalytic destruction efficiencies of the two volatile organic compounds(VOC) included input concentration, reaction time, reaction temperature, and surface area of catalyst. It was found that the input concentration affected the destruction efficiencies of n-hexane and benzene, but that this input-concentration effect depended upon VOC type. The destruction efficiencies increased as the reaction time increased, but they were similar between two reaction times for benzene(50 and 60 sec), thereby suggesting that high temperatures are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Similar to the effects of the input concentration on destruction efficiency of VOCs, the reaction temperature influenced the destruction efficiencies of n-hexane and benzene, but this temperature effect depended upon VOC type. As expected, the destruction efficiencies of n-hexane increased as the surface area of catalyst, but for benzene, the increase rate was not significant, thereby suggesting that similar to the effects of the re- action temperature on destruction efficiency of VOCs, high catalyst surface areas are not always proper for economical thermal destruction of VOCs. Depending upon the inlet concentrations and reaction temperatures, almost 100% of both n-hexane and benzene could be destructed, The current results also suggested that when applying the mesh type transition Metal Pt/SS catalyst for the better catalytic pyrolysis of VOC, VOC type should be considered, along with reaction temperature, surface area of catalyst, reaction time and input concentration.

Effects of Catalyst Metal and Substrate Temperature on a Flame Synthesis of Carbon Nanomaterials (화염을 이용한 탄소나노튜브와 나노섬유의 합성에 미치는 촉매금속 및 기판온도의 영향)

  • Lee, Gyo-Woo;Jurng, Jong-Soo;Hwang, Jung-Ho
    • Journal of the Korean Society of Combustion
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    • v.8 no.2
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    • pp.27-33
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    • 2003
  • Synthesis of carbon nanomaterials on a metal substrate by an ethylene fueled inverse diffusion flame was illustrated. Stainless steel plates were used for the catalytic metal substrate. The effects of catalyst metal particles were investigated through $Fe(NO_3){_3}$ (ferric nitrate, nonahydrate) and $Ni(NO_3){_2}$ (nickel nitrate, hexahydrate). Carbon nanotubes and nanofibers with diameters of $30{\sim}70nm$ were found on the substrate for the case of using SUS304 substrates only and using them with metal nitrates. In case of using metal nitrates, due to the easy activation of the metal particles, the formation and growth of carbon nanomaterials were occurred in the lower temperature region than that of using SUS304 substrates only.

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Preparation of CuO-CeO2 mixed oxide catalyst by sol-gel method and its application to preferential oxidation of CO (졸-겔법에 의한 CuO-CeO2 복합 산화물 촉매의 제조 및 CO의 선택적 산화반응에 응용)

  • Hwang, Jae-Young;Hahm, Hyun-Sik
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.4
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    • pp.883-891
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    • 2017
  • For the preferential oxidation of CO contained in the fuel of polymer electrolyte membrane fuel cell (PEMFC), CuO-$CeO_2$ mixed oxide catalysts were prepared by the sol-gel and co-precipitation methods to replace noble metal catalysts. In the catalyst preparation by the sol-gel method, Cu/Ce ratio and hydrolysis ratio were changed. The catalytic activity of the prepared catalysts was compared with the catalytic activity of the noble metal catalyst($Pt/{\gamma}-Al_2O_3$). Among the catalysts prepared with different Cu/Ce ratios, the catalyst whose Cu/Ce ratio was 4:16 showed the highest CO conversion (90%) and selectivity (60%) at $150^{\circ}C$. As the hydrolysis ratio was increased in the catalyst preparation, surface area increased, and catalytic activity also increased. The highest CO conversions with the CuO-$CeO_2$ mixed oxide catalyst prepared by the co-precipitation method and the noble metal catalyst (1wt% $Pt/{\gamma}-Al_2O_3$) were 82 and 81% at $150^{\circ}C$, respectively, whereas the highest CO conversion with the CuO-$CeO_2$ mixed oxide catalyst prepared by the sol-gel method was 90% at the same temperature. This indicates that the catalyst prepared by the sol-gel method shows higher catalytic activity than the catalysts prepared by the co-precipitation method and the noble metal catalyst. From the CO-TPD experiment, it was found that the catalyst having CO desorption peak at a lower temperature ($140^{\circ}C$) revealed higher catalytic activity.

Characteristics of Rh- Pd- Pt Three-Way Catalysts with Double-Layer Washcoat on the Hydrothermal Aging (이중층 워시코트 Rh-Pd-Pt 삼원촉매의 열적 열하에 따른 반응 특성)

  • Choi Byungchul;Jeong Jongwoo;Son Geonseog;Jung Myunggun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.1
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    • pp.8-16
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    • 2006
  • The research was conducted to characterize of Rh-Pd-Pt TWC with a double-layer washcoat for gasoline vehicle. The physical characteristics on surface of catalyst were inspected by BET, SEM and TEM. The characteristics of catalytic reaction were examined by the TPD/TPR and CO-pulse chemisorption. The catalyst $6Hx(0.35\times11\times3)$ showed superior conversion performance after hydrothermal aging process, which was due to small difference of the surface area between. the fresh and the aged catalyst. The CO-chemisorption and surface area were superior in the 600 cpsi catalyst than other catalysts, this catalyst also shown the higher conversion efficiency of the exhaust emissions. From the TPR test, the conversion performance of the aged catalyst was decreased by the agglomeration and sintering of the PM and metal oxides. From the TPD result, it was found that the NO chemisorption was happed on the bottom-layer washcoat with Pd, and the NO chemisorption was re-happened on the upper-layer washcoat with Pt and Rh in the desorption process.

Polymeric Material Application for The Production of Ceramic Foam Catalyst

  • Sangsuriyan, Anucha;Yeetsorn, Rungsima;Tungkamani, Sabaithip;Sornchamni, Thana
    • International Journal of Advanced Culture Technology
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    • v.3 no.1
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    • pp.21-30
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    • 2015
  • Ceramic foams are prepared as positive images corresponding to a plastic foam structure which exhibits high porosities (85-90%). This structure makes the ceramic foams attractive as a catalyst in a dry reforming process, because it could reduce a high pressure drop problem. This problem causes low mass and heat transfers in the process. Furthermore, the reactants would shortly contact to catalyst surface, thus low conversion could occur. Therefore, this research addressed the preparation of dry reforming catalysts using a sol-gel catalyst preparation via a polymeric sponge method. The specific objectives of this work are to investigate the effects of polymer foam structure (such as porosity, pore sizes, and cell characteristics) on a catalyst performance and to observe the influences of catalyst preparation parameters to yield a replica of the original structure of polymeric foam. To accomplish these objectives industrial waste foams, polyurethane (PU) and polyvinyl alcohol (PVA) foams, were used as a polymeric template. Results indicated that the porosity of the polyurethane and polyvinyl alcohol foams were about 99% and 97%. Their average cell sizes were approximate 200 and 50 micrometres, respectively. The cell characteristics of polymer foams exhibited the character of a high permeability material that can be able to dip with ceramic slurry, which was synthesized with various viscosities, during a catalyst preparation step. Next, morphology of ceramic foams was explored using scanning electron microscopy (SEM), and catalyst properties, such as; temperature profile of catalyst reduction, metal dispersion, and surface area, were also characterized by $H_2-TPR$ and $H_2-TPD$ techniques, and BET, respectively. From the results, it was found that metal-particle dispersion was relatively high about 5.89%, whereas the surface area of ceramic foam catalysts was $64.52m^2/g$. Finally, the catalytic behaviour toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain operating conditions. The approaches from this research provide a direction for further improvement of marketable environmental friendly catalyst production.

The characteristics of grown carbon nanotubes by controlled catalyst preparation at the catalytic chemical vapor deposition (촉매제어를 통한 촉매화학기상증착법으로 성장시킨 탄소나노튜브의 특성분석)

  • Kim, Jong-Sik;Kim, Gwan-Ha;Kim, Chang-Il
    • Proceedings of the KIEE Conference
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    • pp.1378-1379
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    • 2006
  • Carbon nanotubes (CNTs) with few defects and very small amount of amorphous carbon coating have been synthesized by catalytic decomposition of acetylene in $H_2$ over well-dispersed metal particles supported on MgO. The yield, quality and diameters of CNTs were obtained by control of catalyst metal compositions to be used. The optimization condition of carbon nanotubes with high yield is when Co and Mo are in a 1:1 ratio and Fe metal contents to Co is increased on magnesium oxide support. It is also found that the diameter of the as-prepared CNTs can be controlled mainly by adjusting the molar ratio of Fe-Mo, Co-Fe, and Co-Mo versus the MgO support. Our results indicated that desired diameter distribution of CNTs is obtained by choosing or combining the catalyst to be employed.

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A Study on the Esterification Reaction of Succinic Acid and 1,4-butanediol Using an Organic Metal Catalysts (유기금속 촉매를 사용한 Succinic Acid과 1,4-butanediol의 에스테르화반응에 관한 연구)

  • Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.26 no.4
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    • pp.415-421
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    • 2009
  • Esterification reaction between succinic acid[SA] and 1,4-butanediol [BD} was kinetically investigated in the presence of organic metal catalysts (alkyl-silver oxide(ASO),CAT 100E) at $150{\sim}190^{\circ}C$. The reaction rates measured by the amount of distilled water from the reaction vessel. The esterification reaction was carried out under the first order kinetics with respect to the concentration of reactants and catalyst, respectively. The overall reaction order was 2nd. From the examination of relationship between apparent reaction rate constants and reciprocal absolute temperature, the activation energy has been calculate as 146.70 kJ/mol with ASO catalyst and 43.04 kJ/mol with CAT 100E catalyst.