• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.713-719
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• 2016

The NOx conversion properties of Mn-Cu-$TiO_2$ and $V_2O_5$/$TiO_2$ catalysts were studied for the selective catalytic reduction (SCR) of NOx with ammonia. The performance of the catalysts was investigated in terms of their $NOx$ conversion activity as a function of the reaction temperature and space velocity. The activity of the Mn-Cu-$TiO_2$ catalyst decreased with increasing reaction temperature and space velocity. However, the activity of the $V_2O_5$/$TiO_2$ catalyst increased with increasing reaction temperature. High activity of the Mn-Cu-$TiO_2$ catalyst was observed at temperatures below $200^{\circ}C$. H2-TPR and XPS analyses were conducted to explain these results. It was found that the activity of the Mn-Cu-$TiO_2$ catalyst was influenced by the thermal shock caused by the change of the initial reaction temperature, whereas the $V_2O_5$/$TiO_2$ catalyst was not affected by the initial reaction temperature. In the case of catalyst C, the $NO_x$ conversion efficiency decreased with increasing space velocity. The decrease in the $NO_x$ conversion efficiency with increasing space velocity was much less for catalyst D than for catalyst C.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1028-1029
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• 2003

The copolymerization of ethylene and norbornene was carried out with ansa-metallocene and modified methylaluminoxane (MMAO) cocatalyst. The copolymerization behavior was changed with the structure of metallocene catalysts. In addition the catalyst activity was dependent on the structure of MMAO, i.e.. MMAO-4 which contains less i-butyl group compared to MMAO-3A exhibited higher catalyst activity than MMAO-3A. The glass transition temperature and the composition of the produced copolymer were not affected by MMAO type.

• Journal of Hydrogen and New Energy
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• v.27 no.3
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• pp.283-289
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• 2016

In this study, electrochemical characterizations of PdCu/C catalysts that are synthesized by modified polyol method are investigated. Most of all, amount of ethylene glycol (EG) that is used as main component for catalyst synthesis is mainly modulated to optimize synthetic condition of the PdCu/C catalyst, For evaluations about catalytic activity and performance of direct formic acid fuel cell (DFAFC), half cell and full cell tests are implemented. As a result, when amount of EG is 4M, catalytic activities of the PdCu/C catalyst such as peak current of formic acid oxidation and active surface area are best, while maximum power density of DFAFC using the optimized PdCu/C catalyst is better than that using commercial Pd/C (30 wt%) by 6%. Based on that, PdCu/C catalyst synthesized by modified polyol method plays a critical role in improving (i) catalytic activity for formic acid oxidation and (ii) DFAFC performance by employing as anodic catalyst.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4250-4256
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• 2011

Mn catalyst promoted with Cu were prepared and tested for selective catalytic reduction of $NO_x$ with $NH_3$. Performance of each catalyst was investigated for $NO_x$ activity while changing temperature, space velocity, water content and $O_2$ concentration. Hydrogen conversion efficiency of catalyst was also measured in the $H_2$-TPR system. The inhibition effect of water on catalyst was investigated with the on-off control of water supply. High activity of Mn-Cu catalyst was observed for $160{\sim}260^{\circ}C$. It is found that increase of oxygen concentration acts as a promotor to the increase of catalyst activity but water content acts as a inhibitor.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1643-1646
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• 2012

Three Ni-based catalysts with different clay as support were prepared and tested in the hydrogenation of maleic anhydride, among which Ni/clay1 showed best activity and selectivity. Over Ni/clay1 catalyst prepared by impregnation method, 97.14% conversion of maleic anhydride and 99.55% selectivity to succinic anhydride were obtained at $180^{\circ}C$ under a pressure of 1 MPa. Catalytic activity was greatly influenced by the temperature and weighted hourly space velocity. Catalyst deactivation studies showed that this catalyst have a long life time, the yield of MA still higher than 90% even after a reaction time of 60 h. X-ray diffraction (XRD) and $H_2$ temperature programmed reduction (TPR) were use to investigate the properties of the catalyst. XRD and TPR studies showed that Ni was present as $Ni^{2+}$ on the support, which indicated that there was no elemental nickel ($Ni^0$) and $Ni_2O_3$ in the unreduced samples. The formation of Ni was strong impact on catalytic activity.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.2
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• pp.160-167
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• 1993

As the major methanol fueled vehicle exhaust components, formaldehyde & methanol conversion over the existing commercial 3-way catalyst was examined in a labolatory tains different Ag loadings on commercial 3-way catalyst, and german commercial catalysts for methanol engine exhaust manufactured by a commercial manufacturer. Silver catalysts were prepared by the wet impregnation of silver nitrate solution on commercial 3-way catalyst. These catalysts were characterized with BET Surface area and pore size distribution. In general, the formaldehyde(HCHO) conversion of the tested catalysts was similar to that of methanol$(CH_3OH)$. At 100$^\circ$C, which is equivalent to the cold start condition, 5wt% Ag cat. showed the most excellent HCHO and $CH_3OH$ conversion. The order of activity for conversion of HCHO & $CH_3OH$ to carbon dioxide and water vapor was as follows ; 5wt% Ag/3-way cat.>2wt% Ag/3-way cat.>german cat. front(1) > german cat. rear(2) > 10wt% Ag/3-way cat.> commercial 3-wat catalyst. However there was no significant activity difference between those tested catalysts in the hot run condition of 400$^\circ$C. Therefore, it could be concluded that the Ag-modified 3-way catalyst was the most effective and practical catalyst system which could be capable of removal the HCHO and methanol at the special condition of low temperature such as cold start condition.

• Korean Journal of Materials Research
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• v.25 no.4
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• pp.191-195
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• 2015

To improve its textural properties as a support for platinum catalyst, carbon aerogel was chemically activated with KOH as a chemical agent. Carbon-supported platinum catalyst was subsequently prepared using the prepared carbon supports(carbon aerogel(CA), activated carbon aerogel(ACA), and commercial activated carbon(AC)) by an incipient wetness impregnation. The prepared carbon-supported platinum catalysts were applied to decalin dehydrogenation for hydrogen production. Both initial hydrogen evolution rate and total hydrogen evolution amount were increased in the order of Pt/CA < Pt/AC < Pt/ACA. This means that the chemical activation process served to improve the catalytic activity of carbon-supported platinum catalyst in this reaction. The high surface area and the well-developed mesoporous structure of activated carbon aerogel obtained from the activation process facilitated the high dispersion of platinum in the Pt/ACA catalyst. Therefore, it is concluded that the enhanced catalytic activity of Pt/ACA catalyst in decalin dehydrogenation was due to the high platinum surface area that originated from the high dispersion of platinum.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.403-406
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• 1990

Two types of new silica catalysts modified with benzenesulfonic acid derivatives were prepared by esterification or phenylation followed by sulfonation. Both catalysts thus prepared were tested as acid catalysts for 2-propanol dehydration and cumene dealkylation reactions. B catalyst () were more active than A catalyst (). Highter catalytic activity for B catalyst may be accounted for by higher resistance to water, higher acid strength, more acidity, and better thermal stability as compared with A catalyst.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.64-69
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• 2016

The applications of heterogeneous catalyst have been relatively active area of research in the biodiesel process. These catalysts have the benefit of easy recovery and reusability of the catalyst. The objective of this study is to find out significant effect of calcination temperature on $K_2CO_3/{\gamma}-Al_2O_3$ catalytic activity in the biodiesel formation reaction. As a results, the temperature at which a catalyst was calcined had very important influence on the catalytic activity. The catalytic activity increased up to $600^{\circ}C$, but it severely decreased above the temperature. The reduction of catalyst activity at high temperature would be due to the deduction of the active sites of Al-O-K and $Al-O_2-K$.

• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.47-55
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• 1991

Regeneration of carbon-deposited Ni catalyst used for hydrogenation reaction was studied. Deposited carbon was removed by oxidation with various concentrations of oxygen. Activity of the catalysts was tested on aniline hydrogenation as a model reaction. When a carbon-deposited catalyst was treated under oxygen atmosphere, the specific surface area of the catalyst increased and then decreased with the increase of treatment temperature. The treatment temperature which gives maximum specific surface area increased with the decrease of oxygen concentration. Pore size of the support was decreased and sintering of nickel particles was more significant with the increase of oxygen concentration. The catalyst treated under 5 % oxygen concentration recovered its catalytic activity up to 90 % of the initial value, but the treatment under 20 % oxygen concentration gave no significant increase of the catalytic activity. Catalytic activity increased with treatment time when the catalyst was treated under 5 % oxygen concentration, but nearly constant after 1 hour.