• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.507-512
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• 2013

Perovskite-type oxides were successfully prepared using microwave-assisted process, and by XRD, XPS, BET, and $H_2-TPR$. Their catalytic activities for the combustion of benzene were also examined. Most of catalysts studied showed the perovskite crystalline phase with the particle size of 21~35 nm. The $LaMnO_3$ catalyst showed the highest activity and the conversion reached almost 100% at $250^{\circ}C$. The catalysts prepared by microwave-assisted process showed higher activity compared to those prepared sol-gel method. In addition, the catalytic activity was increased with an increase of calcination temperature of $LaMnO_3$-type catalyst. The TPR results on the measurement of redox property showed a good correlation with the order of catalytic activity on the benzene combustion reaction.

• Journal of Hydrogen and New Energy
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• v.22 no.4
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• pp.443-450
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• 2011

The three-reactor chemical-looping process (TRCL) for the production of hydrogen from natural gas is attractive for both $CO_2$ capture and hydrogen production. In this study, redox property of $Fe_2O_3$ and $WO_3$ supported with $ZrO_2$ and $MgAl_2O_4$ were studied with temperature programmed oxidation/reduction (TPO/R) experiment. All metal oxides were prepared by ball mill method. Metal oxides supported with $ZrO_2$ showed the good redox property in TPO and TPR tests. Reduction behavior was matched well the theoretical reduction mechanism. Metal oxides supported with $MgAl_2O_4$ formed a solid solution ($MgFe_{0.6}Al_{1.4}O_4$, $MgWO_4$). $Fe_2O_3$ showed more narrow reaction range and lower reaction temperature than $WO_3$.

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.415-422
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• 1986

The metal-support interaction of copper oxide supported on ${\gamma}$-alumina and silica was studied by X-ray diffraction (XRD) and temperature-programmed reduction(TPR). It was found that XRD pattern of CuO can not be observed up to 5.0wt % copper content for CuO/${\gamma}-Al_2O_3$ while CuO/$SiO_2$ sample shows the CuO pattern even at 2.5wt% copper content. $H_2-$TPR of CuO/${\gamma}-Al_2O_3$ system shows four major peaks at 145${\circ}C$, 185${\circ}C$, 210${\circ}C$, and 250${\circ}C$. In the case of CuO/$SiO_2$, a large peak at 250${\circ}C$ was appeared accompanying a small peak at 425${\circ}C$. Comparing the TPR peaks with that of copper aluminate which was prepared from the calcination of CuO/${\gamma}-Al_2O_3$ at 1000${\circ}C$, the peaks at around 145${\circ}C$, 200${\circ}C$ (185${\circ}C$ and 210${\circ}C$), and 250${\circ}C$ were corresponded to $Cu^+$ ion in CuO interacting ${\gamma}-Al_2O_3$, $Cu^+$ ions in defect sites of ${\gamma}-Al_2O_3$ and $Cu^{2+}$ ion in the bulk CuO layer, respectively. From the results, it was concluded that there is considerable metal-support interaction in CuO on ${\gamma}-Al_2O_3$ and the interaction results in a stabilization of $Cu^+$ ion in the system.

• Journal of the Mineralogical Society of Korea
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• v.22 no.2
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• pp.107-114
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• 2009

In present study, an alternative process for manufacturing ultra marine blue by using kaolin, sulfur, sodium carbonate, silica, and rosin was investigated. From the experiments, it was found in the reductive calcination process that the temperature variation with the bed height of input materials is relatively high due to the inadequate thermal conductivity of them. It was also found that the color of the ultramarine blue manufactured is sensitive for the shape of the input materials and the calcinations conditions, and specially the heating rate is very important to form ultramarine. For manufacturing green ultramarine by using sulfur, sodium carbonate, silicon, and pine resin, an optimum condition was investigated to be the heating rate region below $0.6^{\circ}C/min$, the reaction temperature of $850^{\circ}C$ and the reaction time of 4 hr. At the oxidative calcination process to manufacture ultra marine blue from green ultramarine, the optimum flow rate of air is $500{\sim}550\;{\ell}/kg$ (green ultramarine) and the reaction temperature is $500{\sim}550^{\circ}C$.

• 한국전기화학회:학술대회논문집
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• 2002.07a
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• pp.251-258
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• 2002

[ $Ni-10wt.\%Cr$ ] green sheet를 불활성분위기로 $900^{\circ}C$까지 승온시킨 다음 부분산화$(P_{H2}/P_{H2O}=10^{-2})$후 $1100^{\circ}C$에서 3시간 환원처리를 시키는 소결공정으로 Ni-Cr 고용체 기지 주변에 작은 $Cr_2O_3$ 알갱이가 고르게 분포하는 anode(Anode Sintered in Partial oxidation - Reduction atmosphere; ASPR)를 제조하였으며, creep 변형률이 $2.8\%$로서 미세구조에 따른 creep 특성의 비교를 위해 기존의 환원분위기에서만 소결시킨 anode(Anode Sintered in Reduction atmosphere only; ASR)의 $11\%$보다 우수한 creep 저항성을 나타내었다. $Cr_2O_3$ 알갱이가 분산된 미세구조른 부분산화 시 Cr과 Ni의 산화속도 및 확산속도의 차이로 인해 형성되는 것으로 사료되며, creep 전${\cdot}$후 ASPR 시편의 SEM 및 기공률 분석결과 매우 안정적으로 그 형상 및 구조를 유지하고 있음을 확인할 수 있었다. 또한 ASPR 시편의 전기전도도는 약 $15\times10^6\;S/m$로서 기존 ASR 시편의 전기전도도와 유사함을 알 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.261-261
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• 2009

Anode 지지형 SOFC의 Anode 지지층 제조에 있어 Ni의 입성장이 일어나면 전극의 반응면적이 줄어들어 전기전도도가 감소되므로 소결체의 제조공정이 매우 중요하다. 기공형성제의 함량이 증가할수록 기공율도 증가하였고 기공체의 함량이 20%를 넘어가면서 기공율은 오히려 줄고 밀도도 감소하였다. Anode 지지체는 $1200^{\circ}C$ 이상에서 열처리하여야 입자간 소결이 이루어지며 승온 속도를 $2.5^{\circ}C$ 유지하여 20% 수준의 기공률을 형성하였다. 소결한 음극지지체를 환원하였을 때 35%수준의 개기공을 형성하였고 전해질과의 접착성도 우수하였다.

• Journal of Hydrogen and New Energy
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• v.28 no.4
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• pp.392-400
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• 2017

An experimental study was conducted to investigate behavior of steel surface oxidation with characteristics of the combustion. The excess entalphy combustion in porous media system was applied to implement the direct radiation heating system. The surface oxidation thickness (SOT) of fuel-lean was thicker than the SOT of fuel-rich. Also, the SOT was increased by increasing residence time. Detailed explanations were given by SEM and EDS analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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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.

• Journal of Energy Engineering
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• v.4 no.1
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• pp.76-84
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• 1995

본 연구에서는 코코넛 껍질로부터 제조한 활성탄을 열 및 산소-암모니아의 혼합가스로 전처리하여 표면의 특성 변화와 이산화황 흡착능에 미치는 영향을 살펴보았다. 전처리한 활성탄으로 이산화황 흡착실험을 수행한 결과, 전처리한 활성탄은 기본 활성탄 시료보다 높은 흡착능력을 보였다. 본 연구의 전처리 실험에서는 산소와 암모니아를 주입하여 활성점을 제공하는 산소와 환원성 분위기를 조성하는 질소관능기를 도입하였다. 전처리 조건은 0∼25%의 암모니아와 473∼1273K의 온도이며 처리조건을 변화시킴으로써 표면 기능의 척도가 되는 세공구조와 원소조성 및 표면 관능기 등에 직접적인 영향을 주었다. 흡착능력은 고정층 반응기에서 전자 비틀림 저울로 이산화황 흡착량을 측정하여 비교하였고, 이 과정 중의 활성탄 표면의 특성변화를 원소분석, 승온탈착법, 산-염기 적정법, 주사현미경법 등의 분석 방법을 통해서 알아보았다. 그 결과, 이산화황의 최대 흡착 능력은 온도조건 973∼1173K에서 나타났다. 또한, 암모니아로 처리하지 않은 활성탄에 비하여 암모니아로 처리한 활성탄은 그 주입농도에 관계없이 이산화황의 흡착제거율을 약 48% 정도 향상시켰다.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.74-78
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• 2002

In this study, the solution combustion method was employed to synthesize perovskite PZT ceramics. Multicomponent oxides can be prepared by the solution combustion synthesis using redox exothermic reaction of precursor solutions. The results of DTA/TG showed exothermic peaks in 214$^{\circ}C$ and 350$^{\circ}C$. Those were caused by the differences of the thermal decomposition behavior of oxidizer and fuel. The combustion reaction was completed at 370$^{\circ}C$ during heating procedure, but the product was not transformed into perovskite. The thermal decomposition behavior of both oxidizer and fuel were considered during solution combustion process at 600$^{\circ}C$, which showed tetragonal single phase PZT ceramics with 50 nm crystalline size. The lattice constant a was 3.997 ${\pm}$ 0.001 ${\AA}$ and the lattice constant c was 4.147${\pm}$0.001 ${\AA}$.