• Title/Summary/Keyword: pd catalyst

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Fabrication of a Porous 3C-SiC Based Resistivity Hydrogen Sensor and Its Characteristics (다공성 3C-SiC 기반 저항식 수소센서의 제작과 그 특성)

  • Kim, Kang-San;Chung, Gwiy-Sang
    • Journal of Sensor Science and Technology
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    • v.20 no.3
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    • pp.168-171
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    • 2011
  • Porous 3C-SiC(pSiC) samples with different pore diameters were prepared from poly crystalline N-type 3C-SiC by electrochemical anodization. The pSiC surface was chemically modified by the sputtering of Pd and Pt nano-particles as a hydrogen catalyst. Changes in resistance were monitored with hydrogen concentrations in the range of 110 ppm - 410 ppm. The variations of the electrical resistance in the presence of hydrogen demonstrated that Pd and Pt-deposited pSiC samples have the ability to detect hydrogen at room temperature. Regardless of the catalyst, the 25 nm pore diameter samples showed good response and recovery properties. However, the 60 nm samples showed unstable and slow response. It was found that the pore size affects the catalyst reaction and consequently, results in changes of the sensitivity to hydrogen.

Characteristics of Catalytically Supported Combustion for Gas Turbine Catalytic Combustor;Effects of the inlet shape of catalytic burner (가스터빈용 촉매 연소기를 위한 촉매-화염 복합 연소 특성연구;촉매버너 입구 형상의 영향)

  • Lee, Kyung-Won;Chung, Nam-Jo;Ryu, In-Soo;Cho, Sung-June;Seo, Yong-Seog;Kang, Sung-Kyu;Song, Kwang-Sup;Chun, Kwang-Min
    • 한국연소학회:학술대회논문집
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    • 2002.11a
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    • pp.71-79
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    • 2002
  • The characteristics of the catalytically supported combustion with Pd and Pd/Pt based catalyst using the bench-scaled high pressure combustor have been investigated up to 5atm. This study aimed to investigate combustion characteristics of the stable flame attached to the exit of catalyst bed and NOx emissions with respect to the position of axial and radial direction in the combustor. NOx emissions were increased along the axial distance after the catalyst bed exit and radially decreased from the center to the wall of the combustor. At the higher pressure, the NOx emission decreased slightly due to the lower flame temperature in the combustor at the high pressure.

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Emission characteristics of Natural Gas Fueled Vehicl and its Purification Technologies (천연가스 자동차의 Emission 배출특성 및 저감법)

  • 최병철;이지연;손건석;이귀영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.2
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    • pp.127-135
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    • 1997
  • Experiments have been conducted to investigate emission characteristics of compressed natural gas fueled vehicle(CNGV) by the FTP 75 mode test. Its purification technologies were also investigated. It was found that CNGV was operated on the rich A/F condition by comparison with gasoline vehicle. The Pd catalyst was higher in methane purification performance than Pt and Pd/Pt/Rh catalysts. Up to 60% portion of the accumulative HC emissions(that contains above 80% methane) form CNGV occurs during the first phase of the FTP 75 mode. CO that is exhausted at rich conditions of the air-fuel ratio more than lean conditions should be used for the catalytic reduction of NOX, because the methane is not the effective reduction for NOX in the CNGV with 3-way catalyst system.

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Physical and Chemical Characteristics of Waste Automotive Catalysts (자동차 폐촉매의 물리 화학적 특성)

  • Seo, Seong-Gyu;Moon, Joung-Sun
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.5
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    • pp.819-825
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    • 2000
  • The physico-chemical characteristics and the combustion activities of a waste automotive catalyst were carried out in this study. The physico-chemical characteristics of waste automotive catalyst was examined by EA(Elemental analysis), ICP-AES (Inductively coupled plasma-atomic emission spectrophotometer), and XRD(X-ray diffraction) analysis. Carbon deposit amount was higher in front brick than rear brick of catalyst, and increased with mileage. The content of Pt. Pd and Rh in waste automotive catalyst was different from the car manufacturing company. The combustion activities of waste automotive catalyst were investigated for acetaldehyde as a model VOC in a fixed bed reactor at atmospheric pressure. The catalytic activity of rear brick for acetaldehyde combustion was better than front brick of waste automotive catalyst. The catalytic activity of waste automotive catalyst for acetaldehyde combustion decreased with mileage. The linear relationship between catalytic activity and mileage was negative and has a very excellent correlation. Finally, the waste automotive catalyst has a good catalytic activity for acetaldehyde combustion. and can be used to control of small emission source.

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A optimization study on the preparation and coating conditions on honeycomb type of Pd/TiO2 catalysts to secure hydrogen utilization process safety (수소 활용공정 안전성 확보를 위한 Pd/TiO2 수소 상온산화 촉매의 제조 및 허니컴 구조의 코팅 조건 최적화 연구)

  • Jang, Young hee;Lee, Sang Moon;Kim, Sung Su
    • Journal of the Korea Organic Resources Recycling Association
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    • v.29 no.4
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    • pp.47-54
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    • 2021
  • In this study, the performance of a honeycomb-type hydrogen oxidation catalyst to remove hydrogen in a hydrogen economy society to secure leaking hydrogen. The Pd/TiO2 catalyst was prepared based on a liquid phase reduction method that is not exposed to a heat source, and it was showed through H2-chemisorption analysis that it existed as very small active particles of 2~4 nm. In addition, it was found that the metal dispersion decreased and the active particle size increased as the reduction reaction temperature increased. It was meant that the active metal particle size and the hydrogen oxidation performance were in a proportional correlation, so that it was consistent with the hydrogen oxidation performance reduction result. The prepared catalyst was coated on a support in the form of a honeycomb so that it could be applied to the hydrogen industrial process. When 20 wt% or more of the AS-40 binder was coated, oxidation performance of 90% or more was observed under low-concentration hydrogen conditions. It was showed through SEM analysis that long-term catalytic activity can be expected by enhancing the adhesion strength of the catalyst and preventing catalyst desorption. It is a basic research that can secure safety in a hydrogen society such as gasification, organic resource, and it can be utilized as a system that can respond to unexpected safety accidents in the future.

분자동역학을 이용한 전이금속 나노구조체의 특성연구

  • Yun, Gi-Hun;Jo, Min-U
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.359-370
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    • 2014
  • 두 가지 서로 다른 원소를 포함한 나노 크기의 금속클러스터가 여러 화학반응의 효과적인 촉매로 각광받고 있다. 그래서 본 연구에서는 분자동역학을 이용하여 48개로 구성된 Au-Pd 나노 금속 클러스터의 다양한 구조와 상전이 현상을 살펴보고자 한다.

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