• 제목, 요약, 키워드: metal catalyst

검색결과 747건 처리시간 0.042초

저농도 메탄 연소에서 상용 금속촉매의 활성 (Catalytic Activity of Commercial Metal Catalysts on the Combustion of Low-concentration Methane)

  • 이경환;박재현;송광섭
    • 한국대기환경학회지
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    • v.21 no.6
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    • pp.625-630
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    • 2005
  • This study was focused on the catalytic activity for the combustion of low-concentration methane using various commerical catalysts (six transition metal catalysts in Russia and one rare earth metal (Honeycomb) catalyst in Korea). Catalytic activity was strongly influenced by the type and loading content of metal supported in catalyst. Catalytic performance showed the highest activity in Honeycomb catalyst including rare earth metal, which was the most expensive catalyst, while the next was the catalyst supported Cu with high content (AOK-78-52) and also that supported Cr and Co (AOK-78-56). However, both AOK-78-52 and AOK-78-56 catalysts that were very cheap had lower activation energy than Honeycomb catalyst. In the economical field, both AOK-78-52 and AOK-78-56 catalysts with transition metals showed a good alternative catalyst on the combustion of methane.

Nitrogen doped graphene/cobalt-based catalyst layers of a PEM fuel cell: Performance evaluation and multi-objective optimization

  • Kazeminasab, Bagher;Rowshanzamir, Soosan;Ghadamian, Hossein
    • Korean Journal of Chemical Engineering
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    • v.34 no.11
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    • pp.2978-2983
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    • 2017
  • The proton exchange membrane fuel cell could be made more commercially viable by substituting the expensive platinic catalyst without loss of performance. This should be done simultaneously through optimization and use of a non-precious metal catalyst. In this study, multi-objective optimization of the catalyst layer was done on nonprecious metal catalysts. Nitrogen-doped graphene (NG)-based cobalt was synthesized as a non-precious metal catalyst. Differential equations were solved at the modeling stage by the shooting method, and objective functions were solved at the optimization stage using sequential quadratic programming. NG-based cobalt was evaluated in a cell and then compared with the platinum catalyst. Results present the synthesized non-precious catalyst as an appropriate replacement for existing precious metal catalyst. Also, the polarization curve demonstrates that the current modeling is in good agreement with NG-based cobalt catalyst. Finally, the Pareto curve at the voltage of 0.6 V (and $300A/m^2$ current density in the base case) indicated that the best tradeoff between cost and performance of the catalyst layer was achieved when the current density was increased in the range of 5% to 15%.

디젤 엔진에서 금속 폼을 적용한 SCR 촉매의 특성 분석 (Characteristic Analysis of a SCR System using a Metal Foam in Diesel Engines)

  • 김용래;최교남
    • 한국분무공학회지
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    • v.18 no.4
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    • pp.196-201
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    • 2013
  • SCR(Selective Catalytic Reduction) is a major after-treatment solution to reduce NOx emission in recent diesel engines. In this study, a metal foam is applied as an alternative SCR substrate and tested in a commercial diesel engine to compared with a conventional ceramic SCR system. Basic engine test from ND-13 mode shows that a metal foam catalyst has lower NOx conversion efficiency than a ceramic catalyst especially over $350^{\circ}C$. A metal foam catalyst has characteristics of high exhaust gas pressure before a SCR catalyst and high heat transfer rate due to its material and structure. NOx conversion efficiency of a metal foam catalyst shows an increasing tendency along with the increase of exhaust gas temperature by $500^{\circ}C$. The effect of urea injection quantity variation is also remarkable only at high exhaust gas temperature.

Pd+Rh 삼원촉매에서 촉매체적 및 귀금속량이 정화성능에 미치는 영향 (The Effect of Volume and Precious Metal loading on the Performance of Pd+Rh Three Way Catalysts)

  • 김계윤
    • 한국마린엔지니어링학회지
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    • v.23 no.3
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    • pp.389-397
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    • 1999
  • Recently the use of Pd catalyst have been continued to expand because of cost avaliabilityand performance advantages. Especially the Pd+Rh catalyst instead of the Pt+Rh catalyst had been used for most of three way catalysts because of the more stringent emission standards and its higher temperature effectiveness. The main purpose of this study is to investigate the design parameter impacts on the Pd+Rh cat-alyst for the automotive exhaust catalysts application. This study was investigated on the catalyst efficiency for the volume and the precious metal loading of the Pd+Rh ceramic monolithic cata-lyst. And experiments concerning the effects of volume and precious metal loading on Pd+Rh three way catalysts were conducted to examined the catalyst light-off temperature and conver-sion efficiency on higher volume demonstrated almost similar performance. But their effects on higher precious metal loading demonstrated considerably better performance.

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A review of approaches for the design of high-performance metal/graphene electrocatalysts for fuel cell applications

  • Liu, Jiamin;Choi, Hyoung Jin;Meng, Long-Yue
    • Journal of Industrial and Engineering Chemistry
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    • v.64
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    • pp.1-15
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    • 2018
  • Metal/graphene electrocatalysts have attracted growing attention in recent years due to their high catalyst loadings, good activity, and high stabilities. In this review, we summarize various approaches towards improving the efficiencies of metal/graphene electrocatalysts in terms of both cost and performance, based on optimization of the graphene support and the metal catalyst particles themselves. Thus, four different approaches are examined: (1) increasing the catalyst/support binding energy, (2) inducing additional anchoring and active sites, (3) enlarging the effective catalyst surface areas, and (4) enhancing the intrinsic catalytic activity through modification of the electronic structure. Finally, remarks on necessary future work in this area will be given in the context of producing metal/graphene electrocatalysts better suited to fuel cell applications.

Magnetic Separation of FCC Equilibrium Catalyst by HGMS

  • Xiang, Fazhu;He, Pingbo;Chen, Jin
    • 대한전자공학회:학술대회논문집
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    • pp.770-775
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    • 2001
  • Effects of magnetic field and carrier gas velocity on the magnetic separation of FCC catalyst by a high gradient magnetic separator were studied. The activities of the equilibrium catalyst, the magnetic particles and the nonmagnetic particles were evaluated in a fixed bed microreactor The results showed that heavy metal contaminated catalyst can be selectively separated by means of high gradient magnetic separation at magnetic field 0.5T and carrier gas velocity 0.3m.s$^{-1}$ , and lightly metal contaminated catalyst retained high catalytic activity.

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디젤엔진 배기가스조건하에서의 Pt 및 Ag 담지 알루미나 촉매의 열적 노화 특성과 SOx 피독 특성에 관한 연구 (A Study on the Thermal Aging and SOx Poisoning Characteristics on Alumina Supported Silver Catalyst under Diesel Engine Emission Condition)

  • 신병선
    • 한국대기환경학회지
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    • v.16 no.2
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    • pp.199-208
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    • 2000
  • In this study we investigated on the possibility of platinum and silver catalysts as de-NOx catalyst for activity test of supported metal oxide catalysts. the study was performed with the change of amount of metal and support types. The catalyst was prepared the activity of alumina supported silver catalyst produced by dry and wet impregnation method respectively and the resistance of sulfur for optimum supported silver catalyst,. As a result the activity of alumina supported platinum catalyst was showed at low temperature region but the case of silver catalyst activated at high temperature region. So we finally chose alumina supported silver catalyst as de-NOx target catalyst because alumina supported catalyst showed higher activity than alumina supported platinum catalyst.

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NI/$MgAl_2O_4$코팅된 금속 모노리스 촉매의 수소 생산을 위한 천연가스 수증기 개질 반응특성에 관한 연구 (The Performance of NI/$MgAl_2O_4$ Coated Metal Monolith in Natural Gas Steam Reforming for Hydrogen Production)

  • 최은정;구기영;정운호;이영우;윤왕래
    • 한국수소및신에너지학회논문집
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    • v.21 no.6
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    • pp.500-506
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    • 2010
  • The metal monolith catalyst coated with 15wt% Ni/$MgAl_2O_4$ is applied to the natural gas steam reforming for hydrogen production. To address the improvement of adherence between metal monolith and catalyst coating layer, the pre-calcination temperature as well as the coating conditions of $Al_2O_3$ sol are optimized. When the Fe-Cr alloy monolith is pre-calcined at $900^{\circ}C$ for 6 h, $Al_2O_3$ layer was formed uniformly on the entire surface of the metal substrate. It is seen that the formation of $Al_2O_3$ layer on the monolith surface is essential for the uniform coating of $Al_2O_3$ sol onto the monolith substrate. The monolith catalyst coated with 10wt% $Al_2O_3$ sol shows high $CH_4$ conversion and good thermal stability as compared with the monolith catalyst without $Al_2O_3$ sol coating under severe reaction conditions with high GHSV of 30,000 $h^{-1}$ at $700^{\circ}C$. In addition, the metal monolith catalyst shows higher catalytic activity and better thermal conductivity than 15wt% Ni/$MgAl_2O_4$ pellet catalyst.

폐산화철촉매에 의한 폐수중 Ni, Cu, Fe, Zn이온 회수에 관한 기초연구 (A basic study on the recovery of Ni, Cu, Fe, Zn ions from wastewater with the spent catalyst)

  • 이효숙;오영순;이우철
    • 자원리싸이클링
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    • v.13 no.2
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    • pp.3-8
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    • 2004
  • 석유화학공정에서 발생하는 산화철폐촉매를 이용하여 폐수 중 중금속회수에 관한 기초연구를 실시하였다. Zn, Ni, Cu, 및 Fe의 농도가 200mg/L인 각각의 합성폐수에 폐촉매 첨가량을 변화하여 실험한 바, 각 금속의 98% 회수율을 얻은 폐촉매 첨가량은 Cu 와 Fe 폐수 :2% 이상, Zn 폐수:3% 이상, Ni 폐수 :7% 이상이었다. 또한 폐산화철 촉매로서 Zn, Ni, Cu 및 Fe 금속의 98% 이상 회수할 수 있는 각각의 폐수 pH는 Ni: 10.6 이상, Cu: 8.0 이상, Fe:6.5 이상, Zn:8.5 이상이었다. 따라서 폐산화철 촉매에 의한 폐수 중 중금속 회수는 폐촉매의 알카리성분에 의한 침전이 주 메카니즘이고, 각 금속의 수산화침전 pH이하 폐촉매의 등전점(pH 3.0) 이상의 pH범위에서는 금속이온이 폐촉매 표면에서 물리흡착에 의해 일부 회수된다.

EFFECT OF CATALYST ON THE GROWTH OF CARBON NANOTUBES IN CVD PROCESS

  • Yoon, Young-Joon;Song, Kie-Moon;Lee, Se-Jong;Baik, Hong-Koo
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.137-138
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    • 2000
  • We synthesized highly aligned carbon nanotubes by thermal decomposition of acetylene gas using metal catalyst island. The alignment technique in this experiment is a very efficient method because it does not require any treatments before and after catalyst metal deposition. Alignment of nanotubes was dominated by the uniform diameter and the high density of metal catalysts. In the field emission test, the uniform emission spots on phosphor screen were obtained from the nanotubes in spite of non-aligned tube nature.

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