• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.154-159
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• 2005

In proportion to the increase of industrial development, emission troubles were concerned as global issue. For these reasons, so many researchers and associated institutes effort to reduce pollution with new technology and various devices. As a kind of these methods, we used catalysts as a after-treatment system. At first, we made equipment of model furnace. And various catalysts were equipped at exhaust duct of combustion system, and excess air ratio( ), change cell numbers, catalyst materials(Pt, Pd) were changed as experimental conditions. With these various condition, temperature, NOx, CO, HC, $CO_2$ and $O_2$ concentration were measured. As a result, NOx conversion were increased with increasing of cell number in Pd catalyst. And Pt catalyst were became 100% conversion at 200 and 300 cell. Also, Pt catalyst was better than Pd catalyst ${\alpha}$=1.5 in this condition. In addition, CO and HC concentrations were decreased${\alpha}$=1.5 with Pd catalyst.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.8-16
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• 2006

The research was conducted to characterize of Rh-Pd-Pt TWC with a double-layer washcoat for gasoline vehicle. The physical characteristics on surface of catalyst were inspected by BET, SEM and TEM. The characteristics of catalytic reaction were examined by the TPD/TPR and CO-pulse chemisorption. The catalyst $6Hx(0.35\times11\times3)$ showed superior conversion performance after hydrothermal aging process, which was due to small difference of the surface area between. the fresh and the aged catalyst. The CO-chemisorption and surface area were superior in the 600 cpsi catalyst than other catalysts, this catalyst also shown the higher conversion efficiency of the exhaust emissions. From the TPR test, the conversion performance of the aged catalyst was decreased by the agglomeration and sintering of the PM and metal oxides. From the TPD result, it was found that the NO chemisorption was happed on the bottom-layer washcoat with Pd, and the NO chemisorption was re-happened on the upper-layer washcoat with Pt and Rh in the desorption process.

• 한국응용과학기술학회지
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• 제20권1호
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• pp.33-43
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• 2003

$LiMn_2O_4$ catalyst for $CO_2$ decomposition was synthesized by oxidation method for 30 min at 600$^{\circ}C$ in an electric furnace under air condition using manganese(II) nitrate $(Mn(NO_3)_2{\cdot}6H_2O)$, Lithium nitrate ($LiNO_3$) and Urea $(CO(NH_2)_2)$. The synthesized catalyst was reduced by $H_2$ at various temperatures for 3 hr. The reduction degree of the reduced catalysts were measured using the TGA. And then $CO_2$ decomposition rate was measured using the reduced catalysts. Phase-transitions of the catalysts were observed after $CO_2$ decomposition reaction at an optimal decomposition temperature. As the result of X-ray powder diffraction analysis, the synthesized catalyst was confirmed that the catalyst has the spinel structure, and also confirmed that when it was reduced by $H_2$, the phase of $LiMn_2O_4$ catalyst was transformed into $Li_2MnO_3$ and $Li_{1-2{\delta}}Mn_{2-{\delta}}O_{4-3{\delta}-{\delta}'}$ of tetragonal spinel phase. After $CO_2$ decomposition reaction, it was confirmed that the peak of $LiMn_2O_4$ of spinel phase. The optimal reduction temperature of the catalyst with $H_2$ was confirmed to be 450$^{\circ}C$(maximum weight-increasing ratio 9.47%) in the case of $LiMn_2O_4$ through the TGA analysis. Decomposition rate(%) using the $LiMn_2O_4$ catalyst showed the 67%. The crystal structure of the synthesized $LiMn_2O_4$ observed with a scanning electron microscope(SEM) shows cubic form. After reduction, $LiMn_2O_4$ catalyst became condensed each other to form interface. It was confirmed that after $CO_2$ decomposition, crystal structure of $LiMn_2O_4$ catalyst showed that its particle grew up more than that of reduction. Phase-transition by reduction and $CO_2$ decomposition ; $Li_2MnO_3$ and $Li_{1-2{\delta}}Mn_{2-{\delta}}O_{4-3{\delta}-{\delta}'}$ of tetragonal spinel phase at the first time of $CO_2$ decomposition appear like the same as the above contents. Phase-transition at $2{\sim}5$ time ; $Li_2MnO_3$ and $Li_{1-2{\delta}}Mn_{2-{\delta}}O_{4-3{\delta}-{\delta}'}$ of tetragonal spinel phase by reduction and $LiMn_2O_4$ of spinel phase after $CO_2$ decomposition appear like the same as the first time case. The result of the TGA analysis by catalyst reduction ; The first time, weight of reduced catalyst increased by 9.47%, for 2${\sim}$5 times, weight of reduced catalyst increased by average 2.3% But, in any time, there is little difference in the decomposition ratio of $CO_2$. That is to say, at the first time, it showed 67% in $CO_2$ decomposition rate and after 5 times reaction of $CO_2$ decomposition, it showed 67% nearly the same as the first time.

• 신재생에너지
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• 제6권4호
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• pp.30-40
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• 2010

Syngas from gasification of coal can be converted to SNG(Synthesis Natural Gas) through gas cleaning, water gas shift, $CO_2$ removal, and methanation. One of the key technologies involved in the production of SNG is the methanation process. In the methanation process, carbon oxide is converted into methane by reaction with hydrogen. Major factors of methanation are hydrogen-carbon oxide ratio, reaction temperature and space velocity. In order to understand the catalytic behavior, temperature programmed surface reaction (TPSR) experiments and reaction in a fixed bed reactor of carbon monoxide have been performed using two commercial catalyst with different Ni contents (Catalyst A, B). In case of catalyst A, CO conversion was over 99% at the temperature range of $350{\sim}420^{\circ}C$ and CO conversions and $CH_4$ selectivity were lower at the space condition over 3000 1/h. In case of catalyst B, CO conversion was 100% at the temperature over $370^{\circ}C$ and CO conversions and $CH_4$ selectivity were lower at the space condition over 4700 1/h. Also, conditions to satisfy $CH_4$ productivity over 500 ml/h.g-cat were over 2000 1/h of space velocity in case of catalyst A and over 2300 1/h of space velocity in case of catalyst B.

• Korean Chemical Engineering Research
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• 제60권3호
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• pp.459-467
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• 2022

Pt, PtSn 촉매를 제조한 후, 재분산 연구를 위해 수소분위기에서 소결시킨 후 여러 온도에서 산소처리를 적용하여 백금주석입자의 재분산 정도를 확인하고, 프로판 탈수소 반응실험으로 촉매의 활성을 측정하여 촉매의 물리적, 화학적 상태 변화와 활성의 관계를 이해하고자 하였다. 재분산 처리에 따른 촉매 활성 금속의 상태 및 촉매 입자 간 상호작용 등을 보기 위해 X-선 회절분석(XRD), CO-화학흡착(CO-pulse chemisorption), 수소 승온환원(H₂-TPR) 분석을 실시하였다. 산소 재분산 처리 조건에 따라 백금의 분산도 및 입자 크기, 촉매의 결정상 및 환원 거동이 달라지는 것을 확인하였다. 촉매를 재분산 처리하였을 시 500 ℃에서 산소 처리한 촉매가 가장 높은 전환율과 활성회복률을 보였다. 500 ℃로 산소 처리한 촉매가 백금의 분산도도 비교적 높게 나타나고, 평균 입자 크기가 작아지는 것을 XRD와 CO-화학흡착 결과로부터 확인하여 백금주석입자가 재분산되는 것을 알 수 있었다. 이러한 산소처리에 의한 재분산으로 인해 촉매활성이 회복된다는 것을 알 수 있었고, 백금보다 백금주석 촉매의 활성회복률이 더 높았다.

• 마이크로전자및패키징학회지
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• 제27권2호
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• pp.33-38
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• 2020

광전기화학적 물분해에서 광전극으로 이용되는 GaN은 전해질에 대해 높은 안정성을 가지고 있으며 물의 산화 환원준위를 포함하고 있어 외부전압 없이 물분해가 가능하다. 그러나 GaN 광전극의 경우, 재료 자체의 효율이 낮아 상용화하기에는 부족한 실정이다. 본 연구에서는 광효율을 향상시키기 위해 Cobalt phosphate(Co-pi) 촉매를 광전기증착(Photoelectro-deposition)방법을 통하여 GaN 광전극에 도입하였다. Co-pi 촉매 증착 후 SEM, EDS, XPS분석을 진행하여 Co-pi의 증착 여부 및 증착 정도를 확인하고, Potentiostat를 이용해 PEC 특성을 분석하였다. SEM 이미지를 통해 Co-pi가 GaN 표면 위에 20~25 nm 사이즈의 클러스터 형태로 고르게 증착되어 있는 것을 확인하였다. EDS 및 XPS 분석을 통해 GaN 표면의 입자가 Co-pi임을 확인하였다. 이 후 측정된 PEC 특성에서 Co-pi를 증착 시킨 후 0.5 mA/㎠에서 0.75 mA/㎠로 향상된 광전류밀도 값을 얻을 수 있었다. 향상된 원인을 밝히기 위하여, 임피던스 및 Mott-Schottky 측정을 진행하였고, 측정 결과, 50.35 Ω에서 34.16 Ω으로 감소한 분극저항(R_p)과 증가된 donor 농도(N_D) 값을 확인하였다. 물분해 전 후, 표면 성분을 분석한 결과 물분해 후에도 Co-pi가 남아있음으로써 Co-pi 촉매가 안정적이라는 것을 확인하였다. 이를 통해, Co-pi가 GaN의 효율 향상을 위한 촉매로서 효과가 있음을 확인하였고, 다른 광전극에 촉매로써 적용시켰을 경우, PEC 시스템의 효율을 향상시킬 수 있을 것으로 판단된다.

• 한국수소및신에너지학회논문집
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• 제26권4호
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• pp.339-346
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• 2015

The synthesis of Fischer-Tropsch (FT) oil is the catalytic hydrogenation of CO to give a range of products, which can be used for the production of high-quality diesel fuel, gasoline and linear chemicals. This studied catalyst was prepared Cobalt-supported alumina and silica by the incipient wet impregnation of the nitrates of cobalt, promoter and organic solvent with supports. Cobalt catalysts were calcined at $350^{\circ}C$ before being loaded into the FT reactors. After the reduction of catalyst has been carried out under $450^{\circ}C$ for 24h, FT reaction of the catalyst has been carried out at GHSV of 4,000/hr under $200^{\circ}C$ and 20atm. From these experimental results, we have obtained the results as following; In case of $SiO_2$ catalysts, the activity of 12wt% $Cobalt-SiO_2$ synthesized by organic solvent was about 2 or 3 times higher than the activity of 12wt% $Cobalt-SiO_2$ catalyst synthesized without organic solvent. In particular, the activity of the $Cobalt-SiO_2$ catalyst prepared in the presence of an organic solvent P was two to three times higher than that of the $Cobalt-SiO_2$ catalyst prepared without the organic solvent. Effect of Cr and Cu metal as a promoter was found little. 200 h long-term activity test was performed with a $Co/SiO_2$ catalyst prepared in the presence of an organic solvent of Glyoxal solution.

• 한국응용과학기술학회지
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• 제32권2호
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• pp.281-289
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• 2015

본 연구는 폴리프로필렌(PP) 수지의 Co 및 Mo 촉매에 의한 반응시간과 농도변화에 따른 저온열분해 액화특성을 파악하고자 회분식 반응기를 이용하여 특정 온도(425, 450, $475^{\circ}C$)에서의 전환율을 측정하였다. 열분해 시간은 20~80분으로 설정하였고 생성물은 산업통상자원부에서 고시한 증류성상 온도에 따라 가스, 가솔린, 등유, 경유, 중유로 분류하였다. 그리고 $450^{\circ}C$ 반응온도에서 촉매 사용에 따른 전환율은 모든 반응시간에 있어 Mo 촉매 > Co 촉매 > 무촉매 순이었다. Co 및 Mo 촉매 농도별 PP 전환율 및 열분해 생성물 수율은 Co:Mo=50:50 혼합시 가장 우수한 것으로 나타났다.

• 공업화학
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• 제23권3호
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• pp.253-258
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• 2012

본 연구는 $Pd/TiO_2$ 촉매를 이용한 $CH_4$, CO 동시 산화반응에서 활성점 및 Pd의 산화 상태에 대한 영향을 조사하였다. Pd 함량이 증가할수록 Pd 종(PdO)의 결정성장을 야기시켜 $CH_4$ 산화반응 활성을 증진시켰다. 열처리를 통해 제조된 촉매표면의 Pd 산화상태에 따라 $CH_4$과 CO의 산화반응 활성이 상이한 결과를 나타내었다. XRD와 $H_2-TPR$ 분석으로 소성촉매는 $Pd^{2+}$종, 환원촉매는 $Pd^0$종이 우점하고 있음을 확인하였다. 또한, BET분석을 통해 촉매 활성인자인 비표면적 및 기공부피보다는 Pd의 산화상태가 촉매 활성에 미치는 중요한 인자임을 알 수 있었다. FT-IR 분석을 이용하여 Pd의 산화상태에 따른 $CH_4$과 CO의 반응 메커니즘을 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.529-532
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• 2007

Combined temperature programmed reaction (TPR) and infrared (IR) spectroscopic studies for Fischer- Tropsch reaction have been performed over Ru/SiO2 and Ru-Ag/SiO2 supported catalysts. Reaction of linearly absorbed CO with hydrogen starts at 375 K over Ru/SiO2 catalyst and reaches maximum at 420 K accompanied with an intensity decrease of linear CO absorption. The reaction with bridged absorbed CO peaks around 510-535 K. Addition of Ag yields mixed Ru-Ag bimetallic sites while it suppresses the formation of bridged bonded CO. Formation of methane on this modified surface occurs at 390 K and reaches maximum at 444 K. Suppression of hydrogen on the Ag-doped surface also occurs resulting in the formation of unsaturated hydrocarbons and of CHx intermediates not observed with Ru/SiO2 catalyst. Such intermediates are believed to be the building blocks of higher hydrocarbons during the Fischer-Tropsch synthesis. Linearly absorbed CO is found to be more reactive as compared to bridged CO. The Ag-modified surface also produces CO2 and carbon. On this surface, hydrogenation of CO begins at 390 K and reaches maximum at 494 K. The high temperature for hydrogenation of absorbed CO and C over Ru-Ag/SiO2 catalyst as compared to Ru/SiO2 catalyst is due to the formation of Ru-Ag bimetallic surfaces impeding hydrogen adsorption.