• 대한기계학회논문집B
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• 제34권2호
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• pp.165-171
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• 2010

HCCI 엔진은 배출가스 중 PM과 NOx 가 저감되나, 일반적으로 상용디젤 엔진보다 HC, CO 가 증가하는 특성을 보인다. 특히 과도한 HC 에서 발생하는 SOF 로 인해 total PM 에 영향을 미친다. 이는 HCCI 엔진에서 DOC 를 통한 HC 저감이 중요하며 HC 의 정화성능이 우수한 OC 의 개발이 필요하다. 실험은 모델가스를 이용하여 2Pt/1Pd 의 충전량이 다른 3 종의 OC(600cpsi cordierite)를 가지고 수행하였다. OC 에서 HC, SV, $H_2O$, $O_2$의 조건을 달리하여 OC 성능특성을 $LOT_{50}$에서 평가하였다. 그 결과 CO 는 $170^{\circ}C$에서 3 종의 촉매 모두 90% 이상의 정화특성을 나타내었고 Pd 가 충전 된 OC 는 열화 된 후 Pt 만충전 된 OC 보다 우수한 내구특성을 나타내었다. Fresh 와 aged 된 OC 에서 SV 의 증가 및 $H_2O$의 반응참여는 $LOT_{50}$성능이 낮아지는 결과를 나타내었다.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.43-49
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• 1996

With the recent interest in methanol as a SI engine fuel, aldehyde emissions have become a greater concern. A M-90 fueled passenger car was operated in a chassis dynamometer using FTP 75 driving cycle to examine formaldehyde emissions. Formation process of aldehyde and methods to reduce them are discussed in this paper for a SI-engine passenger car operating by M-90. Aldehyde emissions have been found to be 3 to 7 times higher from M-90 than from gasoline, while CO, NOx, THC are as low or lower than gasoline. Noble metal compositions appeared to play a role in formaldehyde and unburned methanol emission performance. For example, catalyst Pd showed better reduction of both formaldehyde and methanol than catalyst Pt. however, emission rates of formaldehyde and methanol for catalyst Pt were relatively similar to catalyst Pt/Rh.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.105-111
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• 2007

In this study, we investigated the conversion performance of de-NOx catalyst for lean-burn natural gas engine. As a de-NOx catalyst, NOx storage reduction catalyst was composed of Pt, Pd and Rh with washcoat including Ba and Ni, Ru-ZSM-5. Ni, Ru-ZSM-5, which was regarded as a NOx direct decomposition catalyst, was made up of ion exchanged ZSM-5 by 5wt.% Ni or Ru. The performance of de-NOx catalyst was evaluated by NOx storage capacity and catalytic reduction in air/fuel, $\lambda=1.6$. The catalytic reaction was also observed when the added fuel was supplied to fuel rich atmosphere by fuel spike period of 5 seconds. The NOx conversion of the catalysts with Ni-ZSM-5 or Ru-ZSM-5 was mainly caused by the effect of NOx adsorption of Ba rather than the catalytic reduction of Ni, Ru-ZSM-5. Ni, Ru-ZSM-5 catalysts can not use for the NSR catalyst because they have quick process in thermal deactivation.

• Carbon letters
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• 제4권2호
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• pp.74-78
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• 2003

Four kinds of plasma blacks were prepared by plasma pyrolysis under various metallic catalysts coated on honeycomb, and investigated the catalytic effect on the characteristics of the plasma blacks prepared under plasma pyrolysis condition. Pt, Pt-Rh, and Pd catalysts were employed as active materials to prepare the plasma blacks. In the experimental range studied, the metallic catalysts influenced on surface area, particle size, surface oxygen content and electrical conductivity of the plasma blacks prepared. It was showed that more dense particle of plasma blacks were prepared under existence of metallic catalysts. Presence of the metallic catalyst reduces the electrical resistivity of plasma blacks due to the decrease in the amount of oxygen functional groups. The highest electrical conductivity of plasma black was observed in the Pt catalyst and then followed by those Pt-Rh, Pd and bare cordierite honeycomb.

• Journal of Mechanical Science and Technology
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• 제14권6호
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• pp.699-703
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• 2000

Experiments were carried out to investigate the characteristics of the hydrocarbon (HC) emissions and to reduce cold start hydrocarbons in gasoline engines. An HC adsorber was, used and it coated was by Pd/Rh catalyst with zeolite on a honeycomb monolith. The HCs were efficiently trapped at temperatures below $100^{\circ}C by physical adsorption. After adsorption, they were reduced gradually by the catalytic oxidation of Pd/Rh catalysts as the adsorber temperature increased above $100^{\circ}C. Increasing amounts of methane, ethylene and n-butane were emitted as the fuel-air mixture became richer and the engine speed decreased. As the temperature of adsorber increased, high-number carbons into low-number carbons. Thus, the C4 concentration decreased significantly during the first 30 seconds, and the C2 concentration increased continuously.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.169-177
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• 2000

The catalytic heat exchanger, which integrates two functions of heat generation and heat exchange into one equipment, was designed and its characteristics were investigated by the experiment and numerical simulation. The surface of the fin tube was deposited with Pd catalyst. The conversion of the mixture in the catalytic heat exchanger was more significantly affected by the inlet velocity of the mixture than by the inlet temperature and equivalence ratio of the mixture. It was found that the catalytic surface area of the fin tubes should be sufficiently increased to make the combustion intensity of the catalytic heat exchanger as high as possible. Results showed that the fin tubes, placed in the triangularly staggered form, should be adjusted so that the mixture flows uniformly over all the catalytic fin surfaces. Numerical simulation results demonstrated that the flow pattern of the mixture significantly affected the conversion of the mixture.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.67-70
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• 2003

단원계 및 이원계 촉매를 이용하여 나노 감지 소자를 합성하였고, 이를 이용하여 가연성 후막 가스 센서를 제작, 촉매 시스템에 따른 가스 감지 특성을 비교하였다. 단원계의 경우 Pd 및 Pt를 각각 3wt%로, 이원계의 경우 Pd:Pt 농도를 1:2~2:1wt%로 각각 제어하여 평균 입도가 15 nm 인 $SnO_2$ 나노 분말에 도핑, 감지물질을 합성하였다. 그 후 감지물질을 paste로 만들어 인쇄, 가스센서 제작 후 $450{\sim}600^{\circ}C$의 온도로 열처리하였다. 그 결과 이원계 촉매 시스템을 가진 가스 센서는 시효 시간에 따라 감도 값이 변하는 불안정한 현상을 나타내었다, 그러나 단원계 촉매의 경우 시효 시간이 지나도 감도 값이 안정된 현상을 나타내었다. 특히 3wt% pt를 도핑하여 $500^{\circ}C$에서 열처리한 경우 5시간 시효 후에도 감도 값의 변화 폭이 3.5% 이하의 매우 안정된 특성을 나타내었고 반응 시간도 20초 이하로 매우 빠른 응답 특성을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제22권2호
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• pp.183-188
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• 2001

Ionic conjugated polymer, poly(2-ethynyl-N-propargylpyridinium bromide), was prepared by the cyclopolymerization of 2-ethynyl-N-propargylpyridinium bromide on using various transition metal catalysts, or by thermal methods without adding catalyst. The polymerization of 2-ethynyl-N-propargylpyridinium bromide catalyzed by PdCl2 gave the resulting polymers in relatively high yields. The polymer structure was characterized by various instrumental methods to confirm the conjugated polymer backbone structure carrying cumulated pyridine moiety. The polymers prepared by PdCl2 in DMSO or m-cresol were completely soluble in DMF, DMSO, and formic acid. The inherent viscosities of the resulting polymers were in the range of 0.07-0.19 dL/g. Thermal properties of the polymers were also discussed.

• 한국세라믹학회지
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• 제55권1호
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• pp.50-54
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• 2018

This study investigated the long-term durability of catalyst(Pd or Fe)-infiltrated solid oxide cells for $CO_2$/steam co-electrolysis. Fuel-electrode supported solid oxide cells with dimensions of $5{\times}5cm^2$ were fabricated, and palladium or iron was subsequently introduced via wet infiltration (as a form of PdO or FeO solution). The metallic catalysts were employed in the fuel-electrode to promote $CO_2$ reduction via reverse water gas shift reactions. The metal-precursor particles were well-dispersed on the fuel-electrode substrate, which formed a bimetallic alloy with Ni embedded on the substrate during high-temperature reduction processes. These planar cells were tested using a mixture of $H_2O$ and $CO_2$ to measure the electrochemical and gas-production stabilities during 350 h of co-electrolysis operations. The results confirmed that compared to the Fe-infiltrated cell, the Pd-infiltrated cell had higher stabilities for both electrochemical reactions and gas-production given its resistance to carbon deposition.

• 공업화학
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• 제25권3호
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• pp.249-253
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• 2014

다양한 양이온을 가지는 imidazolium hexafluorophosphate를 이용하여 탄소담지 팔라듐 촉매를 제조하여 이를 hexafluoropropylene 수소화 반응에 사용하였다. 팔라듐의 입자형태는 사용된 이온성액체의 양이온에 영향을 받는 것이 관찰되었다. 이온성액체와 팔라듐 입자 사이의 입체적 안정화 영향으로 인하여 양이온 부분의 알킬 길이가 증가할수록 팔라듐입자는 구형에서 원통형으로 변하였다. $500^{\circ}C$에서 소성한 촉매 모두 동일한 결정구조를 형성하였다. 일정한 반응조건에서 양이온에 hexyl기를 가진 이온성액체로 합성한 촉매가 가장우수한 반응성을 보였다.