• Korean Chemical Engineering Research
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• v.44 no.3
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• pp.314-318
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• 2006

Direct formic acid fuel cells (DFAFCs) are potential alternative power sources for portable devices such as cellular phone, personal digital assistants (PDA) and laptop computers. In this study, we developed the catalysts for great performance of fuel cell, and investigated their characteristics by using EDS and SEM. Pt-Pd catalysts showed uniform size and homogeneous distribution. As the content of palladium increased, the performance of DFAFC increased. Pd black showed the greatest performance among the five catalysts tested. Also, Pt-Pd (1:1) catalyst had an excellent maximum power density of $120mW/cm^2$. As the operating temperature increased, fuel cell performance was increased due to a reaction activity increases of catalyst. But, temperature had only a slight effect on the performance of fuel cell in the best activity range of membrane.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.591-598
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• 2005

A three-way catalyst system of a natural gas vehicle (NGV) has characteristics of higher fuel consumption and higher thermal load than a lean-bum catalyst system. To meet stringent emission standards in the future, NGV with the lean-bum engine may need a catalyst system to reduce the amounts of HC, CO and NOx emission, although natural gas system has low emission characteristics. We conducted experiments to evaluate the conversion efficiency of the NOx reduction catalyst for the lean-burn natural gas engine. The NOx reduction catalysts were prepared with the ${\gamma}-Al_{2}O_3$ washcoat including Ba based on Pt, Pd and Rh precious metal. In the experiments, effective parameters were space velocity, spike duration of the rich condition, and the temperature of flowing model gas. From the results of the experiments, we found that the temperature for maximum NOx reduction was around $450^{\circ}C$, and the space velocity for optimum NOx reduction was around $30,000\;h^{-1}$ And we developed an evaluation model of the NOx reduction catalyst to evaluate the conversion performance of each other catalysts.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.165-171
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• 2010

The Homogeneous Charge Compression Ignition (HCCI) engine concept allows for both NOx and particulate matter to be reduced simultaneously, and it is a promising way to meet the next environmental challenges. Unfortunately, HCCI combustion often increases CO and HC emissions. The development of oxidation catalyst (OC) requires high conversion efficiency for CO and HC at low temperature. Conventional oxidation catalyst technologies may not be able to convert these emissions because of the saturation of active catalytic sites. The OC used in this study was 600 cpsi cordierite. Three kinds of OC with different amounts of Pt and Pd were used. The influence of the space velocity (SV), $H_2O$ and $O_2$ concentration was also studied. All types of OCs were found to have over 90% CO conversion efficiencies at $170^{\circ}C$. When in the presence of water vapor, CO conversion was increased, but $C_3H_8$ conversion was decreased. The performance of the OC was not influenced by initial the HC concentration. The 2Pt/Pd catalyst was better in terms of thermal aging than the Pt-only catalyst. The $LOT_{50}$ of both fresh and aged OC was increased with increasing SV and with the presence of $H_2O$.

• Journal of Hydrogen and New Energy
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• v.27 no.3
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• pp.264-269
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• 2016

A simple dry chemical approach was developed in order to load palladium (Pd) as a promoter on Pt/gas diffusion electrode (GDE) for polymer electrolyte membrane fuel cell (PEMFC). Palladium(II) bis (acetylacetonate), $Pd(acac)_2$ was sublimed, penetrated into Pt/GDE and then reduced to Pd nanoparticles simultaneously without any reducing agent and any solvent in a glass reactor of $N_2$ atmosphere at $180^{\circ}C$ for 3, 5 and 15 min. Pd distribution was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and I-V curve was estimated by using a unit cell with $5{\times}5cm^2$ active area.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.1
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• pp.91-98
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• 1997

Y-zeolite and ${\gamma}$-Al$_2$O$_3$ were used as supports on CO and $C_3$H$_{6}$ oxidation for diesel emission control. The catalysts composed of Pd and Pt as active components were wash coated on honeycomb type ceramic substrate. The oxidation of CO and $C_3$H$_{6}$ was carried out over prepared honeycomb in a fixed bed continuous reactor in the temperature range of 20$0^{\circ}C$~50$0^{\circ}C$ and 20,000 GHSV (h$^{-1}$ ). Surface area of Y-zeolite was larger than that of ${\gamma}$-Al$_2$O$_3$ due to channel structure of Y-zeolite. Therefore, high conversion of CO and $C_3$H$_{6}$ could be obtained because of good dispersion of active metals over Y-zeolite. The honeycomb used Y-zeolite as a support showed higher $C_3$H$_{6}$ conversion than that of ${\gamma}$-Al$_2$O$_3$ due to better cracking and isomerization activity of Y-zeolite. PdPt catalyst showed high conversion of CO and $C_3$H$_{6}$ at low temperature region, 20$0^{\circ}C$~30$0^{\circ}C$, for their synergy effects. PdPt/Y-Zeolite catalyst could achieve more than 80％ conversion of $C_3$H$_{6}$ at 30$0^{\circ}C$. The use of Y-zeolite as a support increased CO and $C_3$H$_{6}$ conversion, and decreased SO$_2$ conversion very effectively. Y-zeolite found to have a good adaptability as a support for the diesel emission after treatment system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.917-923
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• 2005

In this paper, effect of catalytic configuration on the sensing properties of $SnO_2$ nanoparticle gas sensitive thick film was investigated. Two types of catalytic configuration, mono and binary, were made on the $SnO_2$ nanoparticle. In case of mono catalytic system, $3 wt\%$ Pd or Pt catalyst was doped onto the $SnO_2$ nanoparticle, respectively. In case of binary catalytic system, Pd and Pt was doped simultaneously with concentration ratio of 1:2 to 2:1 onto the $SnO_2$ nanoparticle. After doping, gas sensitive thick film was printed on alumina substrate and heat-treated at 450 to $600^{\circ}C$. Gas sensing properties was evaluated using 500 to 10,000 ppm $CH_4$ gas. As a result, gas sensitive thick film with binary catalytic system showed unstable phenomena that the gas sensitivity was changed according to aging time. In contrary, the mono catalytic system showed relatively stable phenomena despite of aging time. Especially, gas sensitive thick film doped with $3 wt\%$ Pt catalyst and heat-treated at $500^{\circ}C$ showed good sensing properties such as 0.57 of $R_{3500}/R_{1000}$ and very small variation within $3.5\%$ after aging for 5 hours, and response time was very short less than 20 seconds.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2195-2200
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• 2010

The reaction of $PdCl_2$ dispersed in tetra-n-butylammonium bromide with tributyl amine at $120^{\circ}C$ under argon leads to stable isolable nanometric particles. X-ray diffraction analysis of the material indicated that it is constituted of Pd(0). Transmission electron microscopy analysis of the particles dispersed in acetone shows the mean particle size distribution ($4{\pm}1\;nm$). The isolated palladium nanoparticles can be dispersed in an ionic liquid or in methanol or used in solventless condition for selective hydrogenation of 2-hexyne under mild reaction conditions(0.2 MPa and $20^{\circ}C$). The commercial variety of the Lindlar catalyst was also studied for comparative investigations.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.643-646
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• 2005

직접 메탄올 연료전지는 휴대용기기의 전원으로써 기대되고 있다. 그러나 메탄올의 crossover, 느린 산화반응과 같은 몇 가지 해결해야 할 문제점을 갖고 있다. 이에 메탄올을 대체할 연로로서 이론적으로 높은 기전력 (1.45 V)을 갖는 개미산이 제안되었다. 본 연구에서는 직접 개미산 연료전지에 대한 이전 연구를 바탕으로 개미산 연료전지에 우수한 성능을 나타내는 촉매를 개발하고자 하였다. 기존의 연구에서 Pt-Pd/C 촉매가 개미산에 대해 우수한 산화반응을 보이며 높은 OCP를 나타내어, 본 연구에서는 deposition method을 이용하여 Pt-Pd 촉매를 제조한 후 그 특성을 조사하였다. Pt-Pd 촉매는 이전의 연구에서 우수한 성능을 나타낸 Pt-Pd 촉매보다 상온에서 2배 이상의 우수한 성능을 나타내었다.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.404-409
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• 2006

The catalytic combustion of toluene over Pd-Cu/USY zeolite has been examined by using FT-IR spectroscopy in a closed system under dry and humid conditions. The catalytic combustion of toluene (700 ppmv) in the temperature range of $80-220^{\circ}C$ has been investigated by using a fixed bed reactor. The Pd-Cu/USY catalyst showed the highest catalytic performance with respects to the PdO-CuO/USY and Pd/USY. Comparing to $PdO/Al_2O_3$ catalysts, the slight improvement in conversion was observed over PdO/USY catalysts under humid condition since USY zeolite is hydrophobic substrate and water give an additional oxygen source to zeolite surface like oxygen. The reduced catalysts showed more enhanced catalytic activity due to the reduced activation energy of combustion of toluene than oxidized catalysts such as PdO/USY and PdO-CuO/USY.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2881-2882
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• 2011