• Journal of Korean Society for Atmospheric Environment
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• v.12 no.2
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• pp.121-130
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• 1996

The catalysts composed of Pt, Pd and W as active-components, $Al_{2}O_{3}$ and $SiO_{2}$ as supports, were perpared on the honeycomb type substrate and characterized by BET, SEM, TGA, FT-IR and XRD for diesel emission control. CO, $C_{3}H_{6}$, and $SO_{2}$ oxidation was carried out over these catalysts in a fixed bed continuous flow reactor at the temperatures between 100-500.deg.C and reactant gas was composed of 10 vol.% $O_{2}$, 1 vol.% CO, 0.8 vol.% $C_{3}H_{6}$ and 88.2 vol.% $N_{2}$. It was found that under these experimental conditions, the CO, $C_{3}H_{6}$ oxidation activity of Pt-W catalyst was higher than that of any other prepared catalyst, and this catalyst had also a good inhibition effect on $SO_{2}$ oxidation. Also it was show that the influence of $SO_{2}$ on $Al_{2}O_{3}$ was more sever than that of $SO_{2}$ on $SiO_{2}$.

• Clean Technology
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• v.18 no.1
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• pp.89-94
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• 2012

In this study, we investigated the activity of Pd and Pt supported on acidic Fe-ZSM5 supports for selective catalytic oxidation of ammonia ($NH_3$-SCO). Among the catalysts, Pt/Fe-ZSM5 catalyst exhibited superior $NH_3$-SCO activity to Pd/Fe-ZSM5 catalyst. We also tested Pt/Fe-ZSM5 catalysts with different Fe loading using ion-exchange method to prepare Fe-ZSM5 supports, which resulted in the increased catalytic performance with smaller Fe content: $NH_3$ was oxidized completely at low temperature ($250^{\circ}C$). The physicochemical properties of Fe-ZSM5 were investigated to figure out the relationship between the characteristics of the catalysts and the catalytic activity on $NH_3$-SCO by Inductively coupled plasma-atomic emissions spectrometer (ICP-AES), $N_2$ sorption, X-ray diffraction (XRD), temperature programmed desorption of $NH_3$ ($NH_3$-TPD) technique.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.430-436
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• 2009

Deactivated three-way catalysts which had been exposed to gasoline engine exhaust for a long time were remanufactured by ultra sonic cleaning with distilled water, sulfuric acid solution and impregnation with precious metals (Pt, Pd, Rh). The catalytic properties as well as conversion reactivity of CO, THC and NOx about fresh, aged and remanufactured catalysts were examined. Most of the pollutants deposited on the aged three-way catalysts were removed in the remanufacturing process of those catalysts. At the same time a little amount of precious metals like Pt and Pd were removed in the remanufacturing process. Under the experimental condition used in this study, in the case of the remanufactured catalysts with impregnation of precious metals, the catalytic activities were recovered to almost the same level, or higher level of that of the fresh catalyst.

• Resources Recycling
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• v.26 no.3
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• pp.79-91
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• 2017

The core of Hydrogen Fuel Cell Vehicles (FCV) is polymer solid fuel cell (PEFC), and the core material that generates electrochemical electricity in the cell is platinum catalyst. Platinum is localized in South Africa and Russia, and the world production of Pt is about 178 tons per year, which is expensive and recycled. At present, the amount of Pt used in PEFC is $0.2{\sim}0.1mg/cm^2$. In order to reduce the price of the battery and increase the FCV supply, the target is to reduce the amount of Pt used to $0.05{\sim}0.03mg/cm^2$. $Pt-Pd/Al_2O_3$, Pt/C, Pt/GCB, Pt/Au/C, PtCo/C, PtPd/C, etc. by using polyol method using nano Pt, improved Cu-UPD/Pt substitution method and nano-capsule method, Have been researched and developed, and there have been reported techniques for improving the activity of Pt catalysts and stabilizing them. This paper investigates the production technology of nano-Pt and nano-Pt catalysts, recycling of spent Pt catalysts and application trends of Pt catalysts.

• Journal of Advanced Marine Engineering and Technology
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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.

• Clean Technology
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• v.16 no.1
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• pp.19-25
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• 2010

In this work, the conversion of crystalline cellulose into polyols in the presence of hydrogen was examined over noble metal (Pt, Ru, Ir, Rh, and Pd) catalysts supported on activated carbon. For comparison, Pt/${\gamma}-Al_2O_3$ and Pt/H-mordenite were also investigated. Several techniques: $N_2$ physisorption, X-ray diffraction(XRD), inductively-coupled plasma-atomic emission spectroscopy (ICP-AES), temperature-programmed reduction with $H_2$ ($H_2$-TPR) and CO chemisorption were employed to characterize the catalysts. The cellulose conversion was not strongly dependent on the types of the catalyst used. Pt/AC showed the highest yields to polyols among activated carbon-supported noble metal catalysts, viz. Pt/AC, Ru/AC, Ir/AC, Rh/AC and Pd/AC.

• Journal of Korean Society for Atmospheric Environment
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• v.1 no.1
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• pp.43-51
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• 1985

This study is concerned with the oxidation of carbon monoxide on platinum and platinum-palladium catalysts. Catalysts were made by the impregnation method and flow reactor was used in the catalytic reaction. As for the mixed gases, carbon monoxide concentration varied from 1 to 4% and that of oxygen from 1 to 4%. $N_2$ was used as carrier gas and GHSV varied from 24, 000 $h^{-1} to 60, h^{-1}$. The temperature range was from 200 to $600^\circ$C. It was also taken into consideration that the heat and mass transfer resistance of our catalysts was negligible in the study. Experimental results showed that platinum-palladium catalyst was about 1.5-3.9% superior to platinum catalyst in conversion yield. When we used platinum-palladium catalyst, we observed that carbon monoxide oxidation was found to be 1 st order with respect to carbon monoxide concentration. Activation energy of the catalyst was 23.5 kcal/mol.

• Journal of Energy Engineering
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• v.18 no.2
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• pp.141-146
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• 2009

In present work, we study the hydrogen storage of MWNT decorated with bimetallic Pt and Pd nanosize catalysts by Thermal Vapor Deposition [TVD]. The size of Pt and Pd particles is controlled as 5nm, 3nm, respectively by TVD. Before hydrogen storage measurement, the sample was heated for 1hr at $200^{\circ}C$ in H2 atmosphere. The Hydrogen sto rage of the sample was performed at room temperature and 33~34atm. The hydrogen storage of this composite showed 3.2wt% at 298K and 34atm, for three times. At 4th cycle, hydrogen storage is decreased to 1.5wt%, owing to the aggregation of bimetallic Pt and Pd nano particles.

• Resources Recycling
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• v.3 no.1
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• pp.17-24
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• 1994

Recovery of precious metal values from petrochemical spent catalyst is important from the viewpoint of environmental protection and resource recycling. Two types of spent catalysts were used in this study. One used in the manufacture of ethylene contains 0.3% Pd in the alumina substrate. The other used in oil refining contains 0.3% Pt and 0.3% Re. Both spent catalysts are roasted to remove volatile matters as carbon and sulfur. Then, metallic Pd powder from Pd spent catalyst is obtained in the course of grinding, hydrochloric acid or aqua regia leaching and cementation with iron. For the recovery of Pt and Re from Pt-Re spent catalyst, Pt and Re are leached with either HCI or aqua regia, first. Metallic Pt powder is recovered from the leach solution by cementation with Fe powder. Re in sulfide form is precipitated by the addition of sodium sulfide to the solution obtained after Pt recovery. It is found that 6N HCI can be successfully used as leaching agent for both types of spent catalyst. 6N HCI is considered to be better than aqua regia in consideration of reagent and equipment cost.

• 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.