• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.341-347
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• 2023

In PEMFC, PtCo/C alloy catalysts are widely used because of good performance and durability. However, few studies have been reported on the durability of carbon supports of PtCo/C evaluated at high voltages (1.0~1.5 V). In this study, the durability of PtCo/C catalysts and Pt/C catalysts were compared after applying the accelerated degradation protocol of catalyst support. After repeating the 1.0↔1.5V voltage change cycles, the mass activity, electrochemical surface area (ECSA), electric double layer capacitance (DLC), Pt dissolution and the particle growth were analyzed. After 2,000 cycles of voltage change, the current density per catalyst mass at 0.9V decreased by more than 1.5 times compared to the Pt/C catalyst. This result was because the degradation rate of the carbon support of the PtCo/C catalyst was higher than that of the Pt/C catalyst. The Pt/C catalyst showed more than 1.5 times higher ECSA reduction than the PtCo/C catalyst, but the corrosion of the carbon support of the Pt/C catalyst was small, resulting in a small decrease in I-V performance. In order to improve the high voltage durability of the PtCo/C catalyst, it was shown that improving the durability of the carbon support is essential.

• Carbon letters
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• v.20
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• pp.47-52
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• 2016

Physical and electrochemical qualities were analyzed after KOH activation of a direct methanol fuel cell using needle coke as anode supporter. The results of research on support loaded with platinum-ruthenium suggest that an activated KOH needle coke container has the lowest onset potential and the highest degree of catalyst activity among all commercial catalysts. Through an analysis of the CO stripping voltammetry, we found that KOH activated catalysis showed a 21% higher electrochemical active surface area (ECSA), with a value of 31.37 m² /g, than the ECSA of deactivated catalyst (25.82 m² /g). The latter figure was 15% higher than the value of one specific commercial catalyst (TEC86E86).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1248-1254
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• 2003

Carbon nanotubes(CNTs) are grown by using Co catalyst metal. CNTs fabricated by PECVD(plasma enhanced chemical vapor deposition) method are studied in terms of surface reaction and surface structure by TEM and Raman analysing method and ate analysed in its electrical field emission characteristics with variation of space between anode and cathode. Acetylene(C$_2$H$_2$) gas is used as the carbon source, while ammonia and hydrogen gas are used as catalyst and dilution gas. The CNTs grown by hydrogen(H$_2$) gas plasma indicates better vortical alignment, lower temperature process, and longer tip, compared to that grown by ammonia(NH$_3$) gas plasma. The CNTs fabricated with Co(cobalt) catalyst metal and PECVD method show the multiwall structure in mid-circle type in tip-end and the inner vacancy of 10nm. Emission properties of CNTs indicate the turn-on field to be 2.6 V/${\mu}{\textrm}{m}$ We suggest that CNTs can be possibly applied to the emitter tip of FEDs and high brightness flat lamp because of low temperature CNTs growth, low turn-on field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.71-75
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• 2003

Carbon nanotubes(CNTs) are grown by using Co catalyst metal. CNTs fabricated by PECVD(plasma enhanced chemical vapor deposition) method are studied in terms of surface reaction and surface structure by TEM and Raman analysing method and are analysed in its electrical field emission characteristics with variation of space between anode and cathode. Acetylene($C_2H_2$) gas is used as the carbon source, while ammonia and hydrogen gas are used as catalyst and dilution gas. The CNTs grown by hydrogen($H_2$) gas plasma indicates better vertical alignment, lower temperature process and longer tip, compared to that grown by ammonia($NH_3$) gas plasma. The CNTs fabricated with Co(cobalt) catalyst metal and PECVD method show the multiwall structure in mid-circle type in tip-end and the inner vacancy of 10nm. Emission properties of CNTs indicate the turn-on field to be $2.6\;V/{\mu}m$. We suggest that CNTs can be possibly applied to the emitter tip of FEDs and high brightness flat lamp because of low temperature CNTs growth, low turn-on field.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3194-3201
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• 2023

In water-cooled power reactor, hydrogen is generated in case of steam zirconium reaction during severe accident condition and later on in addition to hydrogen; CO is also generated during molten corium concrete interaction after reactor pressure vessel failure. Passive Autocatalytic Recombiners (PARs) are provided in the containment for hydrogen management. The performance of the PARs in presence of hydrogen and carbon monoxide along with air has been evaluated. Depending on the conditions, CO may either react with oxygen to form carbon dioxide (CO2) or act as catalyst poison, reducing the catalyst activity and hence the hydrogen conversion efficiency. CFD analysis has been carried out to determine the effect of CO on catalyst plate temperature for 2 & 4% v/v H₂ and 1-4% v/v CO with air at the recombiner inlet for a reported experiment. The results of CFD simulations have been compared with the reported experimental data for the model validation. The reaction at the recombiner plate is modelled based on diffusion theory. The developed CFD model has been used to predict the maximum catalyst temperature and outlet species concentration for different inlet velocity and temperatures of the mixture gas. The obtained results were used to fit a correlation for obtaining removal rate of carbon monoxide inside PAR as a function of inlet velocity and concentrations.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.223-226
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• 2005

For $CO_2-free$ hydrogen production and better utilization of the produced carbon, catalytic decomposition of methane over rubber-grade carbon blacks manufactured from coal tar was carried out. The catalytic activities of several domestic carbon blacks were compared. A pelletized carbon black exhibited considerably lower activity and activation energy than the fluffy( loose) carbon black of the same grade. This difference is considered due to the binder that was added during pelletization. For pelletized carbon blacks, a tendency was observed that the activity per unit mass of catalyst increased with the specific surface area of the carbon black. Another tendency was also observed that the activation energy increased with the primary particle size or decrease of the specific surface area.

• Carbon letters
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• v.9 no.1
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• pp.47-60
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• 2008

Understanding the exact structure and surface characteristics of carbon materials is very important for design, synthesis, and utilization of the best carbon form with particular functions and high performance for practical applications such as selective adsorption adsorbents, energy storage materials, catalysts or catalyst supports, etc. This review paper focuses on carbon surface properties and the interaction between gaseous or liquid substances and carbon surface. Catalytic functions of carbon materials are reviewed including recent progress in synthesis and applications of nano-carbons.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.188-190
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• 2007

The MEA with the catalyst layer containing PtRu black and 60 wt. %Pt/C as their anode and cathode catalysts. For find to effect of carbon support, the MEA with platinum black for cathode catalyst was fabricated. The performance of the MEA with the catalyst layer containing (PtRu black:60 wt.% Pt/C) as their anode and cathode catalyst has shown competitively higher value than the performance of the MEA with the catalyst layer containing (PtRu black:Pt black) as their anode and cathode catalyst.

• Applied Chemistry for Engineering
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• v.4 no.3
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• pp.522-529
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• 1993

To raise the utilization of precious platinum currently used as catalyst for PAFC's electrode, it is very important to make fine particles of platinum. This study, for preparing highly dispersed platinum catalyst on carbon black, method. And then loading yield of platinum catalyst on carbon black and the particle size were investigated by DCP and XRD and/or TEM respectively. The colloid method by which platinum particle size could be reduced as small as below $30{\AA}$ showed the best result among them, and the loading yield of platinum catalyst on carbon black was above 99%.

• New & Renewable Energy
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• v.5 no.2
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• pp.9-14
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• 2009

Automobile Shredder Residue (ASR) is very appropriate in a gasification melting system. Gasification melting system, because of high reaction temperature over than $1,350^{\circ}C$, can reduce harmful materials. To use the gasification processes for hydrogen production, the high concentration of CO in syngas must be converted into hydrogen gas by using water gas shift reaction. In this study, the characteristics of shift reaction of the high temperature catalyst (KATALCO 71-5M) and the low temperature catalyst (KATALCO 83-3X) in the fixed - bed reactor has been determined by using simulation gas which is equal with the syngas composition of gasification melting process. The carbon monoxide composition has been decreased as the WGS reaction temperature has increased. And the occurrence quantity of the hydrogen and the carbon dioxide increased. When using the high temperature catalyst, the carbon monoxide conversion ratio ($1-CO_{out}/CO_{in}$) rose up to 95.8 from 55.6. Compared with average conversion ratio from the identical synthesis gas composition, the low temperature catalyst was better than the high temperature catalyst.