• 한국응용과학기술학회지
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• 제17권2호
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• pp.139-143
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• 2000

There appeared enhancements of the conversion of methane by adding a small amount of CO in the aromatization reaction of methane using the Mo-zeolite catalyst. In case of adding $CO_{2}$, $CO_{2}$ changed to CO first, and then the conversion reaction occurred. It was observed by using isotopes as reactants that CO is related to the aromatization reaction of methane.

• 전기화학회지
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• 제16권1호
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• pp.52-58
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• 2013

고분자 전해질 연료전지(Polymer Electrolyte Membrane Fuel Cell, PEMFC) 상용화를 위해 해결해야 할 과제 중의 하나인 가격 저감을 이루기 위한 방법으로 백금 촉매를 대신할 비귀금속(non-precious metal) 촉매 제조에 관한 연구를 수행하였다. 비귀금속 촉매의 합성은 산소환원반응(oxygen reduction reaction, ORR)의 활성점으로 알려져 있는 코발트-질소(Co-N) 결합을 형성하기 위해 질소를 포함하는 폴리아닐린(PANI)과 코발트염(Co precursor), 그리고 카본 블랙(C)을 일정한 비율대로 혼합한 후 특별한 열처리 과정 없이 단순한 화학적 환원법에 제조되었다. 제조된 Co-PANI-C 복합 촉매의 구조 분석을 위해 X-선 회절분석(X-ray diffraction, XRD)과 열중량분석(thermogravimetric analysis, TGA)을 실시하였고, ORR에 대한 활성을 평가하기 위해 rotating disk electrode(RDE) 및 rotating ring disk electrode(RRDE) 측정을 수행하였다. 그 결과 Co-PANI-C 복합 촉매는 ORR반응에 대한 개시 전압은 백금 촉매보다 60 mV 밖에 낮지 않은 값을 보였지만, 반응에 의해 발생되는 환원 전류는 여전히 백금 촉매보다 낮은 값을 보였다. 이 밖에도 전극 회전 속도에 따른 ORR 특성 변화, 전압 사이클 회수에 따른 내구성 변화, 연료전지 적용 시 성능 변화에 대해 논의할 것이다.

• 한국응용과학기술학회지
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• 제33권4호
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• pp.676-685
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• 2016

본 연구는 폴리스타렌(PS) 수지의 유화공정 효율성 향상을 위해 저온열분해 회분식 반응기를 이용하여, 단일 PS 수지와 Co 및 Mo 촉매를 각각 첨가한 PS 수지를 반응온도(425, 450, $475^{\circ}C$), 반응시간(20~80분, 15분 간격), 촉매 농도변화에 따른 PS수지의 액화생성물 전환율을 측정하였다. 최적의 열분해 조건은 반응온도 $450^{\circ}C$, 반응시간 35분으로 판단되며, 전환된 액화생성물의 주요 성분은 GC/MS 분석결과 스타이렌 및 벤젠유도체가 대부분으로 나타났다. 생성물은 산업통상자원부에서 고시한 증류성상 온도에 따라 가스, 가솔린, 등유, 경유, 중유로 분류하여 그 수율을 측정하였다. 그리고 $450^{\circ}C$ 반응온도에서 촉매 사용에 따른 전환율은 Co 촉매 > Mo 촉매 > 무촉매 순이었으며, 생성물 중 가스, 등유, 경유수율은 Mo 촉매, 가솔린은 무촉매, 중유는 Co 촉매에서 우수한 것으로 나타났다. Co 및 Mo 촉매 혼합 농도별 전환율 및 열분해 생성물 수율은 Co 촉매 100% 사용 시 가장 우수한 것으로 판단된다.

• 청정기술
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• 제5권2호
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• pp.63-68
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• 1999

The activities of Ni(20wt%)/$La_2O_3$, Ni(20wt%)/${\gamma}-Al_2O_3$, and Ni(20wt%)/$SiO_2$ catalyst for $CO_2$ reforming of $CH_4$ were investigated in a fixed bed flow reactor under atmospheric condition. Catalyst characterization using XRD, TEM, SEM, BET analysis were also conducted. The catalytic activity of Ni(20wt%)/$La_2O_3$ catalyst has relatively superior to that of Ni(20wt%)/${\gamma}-Al_2O_3$ and Ni(20wt%)/$SiO_2$ catalyst. The good activity of Ni(20wt%)/$La_2O_3$ catalyst seems to depend on reduced $Ni^{\circ}$ phases of NiO($\rightarrow$ Ni + O), $LaNiO_3$($\rightarrow$ $Ni+La_2O_3$), Ni crystalline phases, and decoration of Ni phases by lanthanum species is also an important factor. Ni(20wt%)/${\gamma}-Al_2O_3$ and Ni(20wt%)/$SiO_2$ catalyst due to surface acidity resulted in the deposition of wisker type and encapsulate carbon on the surface of catalyst, but Ni(20wt%)/$La_2O_3$ catalyst did not show carbon on the surface of catalyst up to 8.5hr reaction.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1687-1691
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• 2014

This study reports on the synthesis of carbon nanofibers via chemical vapor deposition using Co and Cu as catalysts. In order to investigate the suitability of their catalytic activity for the growth of nanofibers, we prepared catalysts for the synthesis of carbon nanofibers with Cobalt nitrate and Copper nitrate, and found the optimum concentration of each respective catalyst. Then we made them react with Aluminum nitrate and Ammonium Molybdate to form precipitates. The precipitates were dried at a temperature of $110^{\circ}C$ in order to be prepared into catalyst powder. The catalyst was sparsely and thinly spread on a quartz tube boat to grow carbon nanofibers via thermal chemical vapor deposition. The characteristics of the synthesized carbon nanofibers were analyzed through SEM, EDS, XRD, Raman, XPS, and TG/DTA, and the specific surface area was measured via BET. Consequently, the characteristics of the synthesized carbon nanofibers were greatly influenced by the concentration ratio of metal catalysts. In particular, uniform carbon nanofibers of 27 nm in diameter grew when the concentration ratio of Co and Cu was 6:4 at $700^{\circ}C$ of calcination temperature; carbon nanofibers synthesized under such conditions showed the best crystallizability, compared to carbon nanofibers synthesized with metal catalysts under different concentration ratios, and revealed 1.26 high amorphicity as well as $292m^2g^{-1}$ high specific surface area.

• 한국수소및신에너지학회논문집
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• 제15권2호
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• pp.137-143
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• 2004

For hydrogen generation from aqueous alkilne $NaBH_4$ solution, Co-B catalyst was prepared by chemical reduction method using $NaBH_4$ as a reduction chemical. Effects of solution temperature, amount of catalyst loading, $NaBH_4$ concentration, and NaOH (a base-stabilizer) concentration on the hydrogen generation rate were exmanined. Compared to Ru catalyst generally used, the low-cost Co-B catalyst exhibited almost comparable activity to the hydrogen generation reaction.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.92-100
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• 2000

The model gas reaction tests were carried out to investigate the purification characteristics of methane on the exclusive catalyst for NGV. The experiment was conducted with the factors which affect the conversion efficiency of methane, such as Redox ratio, coexistence components of CO, MO, $H_2$O, precious metals and additives. The catalyst loaded with larger amount of pd and with additive La showed lower light-off temperature. In the presence of CO and NO, the conversion efficiency of methane was varied according to the kind of additive loaded. The conversion efficiency of methane was dropped for the catalyst loaded with La under lean air-fuel ratio, while it increased for the one loaded with Ti+Zr for the same condition. It was shown that the water vapor inhibited methane from oxidation by its poisoning on the surface of catalyst.

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1785-1789
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• 2002

2,2'-Dichlorohydroazobenzene was prepared by selective hydrogenation of o-nitrochlorobenzene with hydrogen in the presence of 0.8% and 5% Pd/C catalyst. O-Chloroaniline was a minor product in the catalytic hydrogenation of o-nitrochlorobenzene. The effects of base, Pd/C catalyst, and co-catalyst were discussed on catalytic hydrogenation. 2,2'-Dichlorohydroazobenzene, as an intermediate, was rearranged to 3,3'-dichlorobenzidine after reacting with HCl. It was shown that selectivity of catalytic hydrogenation of o-nitro-chlorobenzene is affected strongly by concentration of base, Pd/C catalyst, and co-catalyst. $^1Hand^{13}C$NMR spectroscopy confirmed the chemical structures of 2,2'-dichlorohydrazobenzene and 3,3'-dichlorobenzidine.

• 대한화학회지
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• 제34권2호
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• pp.165-170
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• 1990

광학활성인 $[Co(edta)]^- 착물과 [Co(Hedta)Cl]^- 착물의 반응성과 구조적인 변화를 여러 가지 촉매(H^+, OH^-, 그리고 Cd^{2+})의 존재하에서 연구하였다. Δ-[Co(edta)]- 착물에 촉매로서 H+ 또는 OH-를 각각 작용시키면 착물에 대한 리간드의 G-ring이 열리면서, 광학활성인 [Co(Hedta)OH_2]착물과 라세미-[Co(edta)OH]^{2-} 착물이 생성된다. (-)546-[Co(Hedta)Cl]- 착물에 촉매로서 Cd^{2+}$를 작용시키면, 고리닫힘이 일어나 Δ-[Co(edta)]-착물이 생성되어지고, 이 때 절대배치는 유지되어진다.

• Nuclear Engineering and Technology
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• 제55권9호
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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.