• 공업화학
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• 제23권2호
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• pp.190-194
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• 2012

다양한 상용 $TiO_2$ 담체를 이용한 10 wt%의 Mn계 촉매를 습윤함침법으로 제조하여 $NH_3$에 의한 NO의 저온 선택적 촉매환원법(SCR) 반응 특성을 연구하였다. 촉매의 특성은 BET, XRD, XPS 그리고 TPR과 같은 물리화학적 분석을 통해 수행되었다. MnOx/$TiO_2$ 촉매의 MnOx 표면밀도는 비표면적에 영향을 받는다. 고분산된 망간산화물에 의한 낮은 MnOx surface density로 저온 SCR 활성이 증가하고 망간산화물의 $MnO_2$에서 $Mn_2O_3$로 환원되는 온도가 감소되었다. 우수한 SCR활성을 위해서는 망간산화물을 높은 비표면적을 가진 $TiO_2$에 담지되어야 하고 고분산된 비정질종이 존재해야 한다.

• 공업화학
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• 제22권3호
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• pp.308-311
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• 2011

하수슬러지 촤에 MnOx를 담지한 촉매를 사용하여 $NH_3$를 환원제로 하는 선택적 촉매 환원반응의 반응 메커니즘 분석을 수행하였다. XRD 분석 결과 활성 Mn phase는 $Mn_3O_4$인 것으로 여겨졌다. 또한 $150^{\circ}C$ 이하에서는 흡착반응이 주요한 질소산화물 저감 메커니즘으로 작동하였으나, $100{\sim}150^{\circ}C$에서는 환원반응도 질소산화물 저감에 관여하는 것으로 보여졌다. 실험결과에 기초하여 활성 촤와 여기에 MnOx를 담지한 촤에서의 반응속도상수를 비교하였다. MnOx 담지촤는 높은 충돌계수와 낮은 활성화 에너지에 기인하여 높은 반응속도 상수와 높은 NOx 제거 효율을 나타내었다. 두 가지 촤 모두 본 실험 조건하에서 활성화 에너지는 상대적으로 낮았다(10~12 kJ/mol).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.175.2-175.2
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• 2014

Graphene (G) has been modified with palladium, copper, and manganese oxide nanoparticles (NPs), and their catalytic applications have been studied in C-C coupling reactions and methylmercaptan (CH3SH) decomposition reactions. In this research, graphite oxide (GO) sheets were exfoliated and oxidized from graphite powder and impregnated with metal precursors including Pd2+, Cu2+, and Mn2+. The thermal treatments of the metal impregnated GO in preferred gas environments produced Pd NPs on graphene (Pd/G), PdO NPs on GO (PdO/GO), and CuOx and MnOx NPs on graphene (CuOx/MnOx/G). In case of Pd/G and PdO/GO, the TEM images show that, although the mean size of the Pd NPs changed significantly before and after the C-C coupling reaction, that of the PdO NPs didn't, implying that the PdO/GO was superior to Pd/G in terms of the recyclability. Also, we demonstrate that the CuOx/MnOx/G exerts the excellent catalytic efficiency in CH3SH decomposition reaction comparing with conventional catalysts. The chemical and electronic structural changes were investigated using XRD and XPS.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.28.2-28.2
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• 2011

The selective catalytic reduction (SCR) of NOx by $NH_3$ is well known as one of the most convenient, efficient, and economical method to prevent NOx emission in flue gas from stationary sources. The degradation of the reactivity is the obstacle for its real application, since high concentrations of sulfur dioxide and thermal factor would deactivate the catalyst. It is necessary to develop high stability of catalysts for low-temperature SCR. Among the transition metal oxides, $WO_3$ is known to exhibit high SCR activity and good thermal stability. The $MnOx-WO_3-TiO_2$ catalysts prepared by sol-gel method with various $WO_3$ contents were investigated for low-temperature SCR. These catalysts were observed in terms of micro-structure and spectroscopy analyses. The $WO_3$ catalyst as a promoter is used to enhance the thermal stability of catalyst since it increases the phase transition temperature of $TiO_2$ support. It was found that the addition of tungsten oxides not only maintained the temperature window of NO conversion but also increased the acid sites of catalyst.

• 한국재료학회지
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• 제2권4호
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• pp.263-269
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• 1992

본 실험에서는 낮은 음의 온도계수를 갖는 저온 소결 유전체에 대해 연구하였다. 새로 개발된 재료의 조성은 Ti$O_2$(100-X) CuOx(X=1~5wt%)에 미량의 Mn$O_2$를 첨가 하였다. CuO를 첨가하지 않은 경우에는 저온 (90$0^{\circ}C$) 에서 소결이 진행되지 않았다. CuO 함량이 증가할수록 저온에서 소결이 가능하였으나, 유전율이 낮아지고 유전손실은 증가 하였다. Mn$O_2$를 0.6wt% 첨가한 경우 유전율과 Q값이 가장 높게 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제16회 학술발표회 논문개요집
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• pp.82-82
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• 1999

• 한국재료학회지
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• 제22권8호
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• pp.385-389
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• 2012

Significant improvements in the switching voltage distribution are required for the development of unipolar resistive memory devices using $MnO_x$ thin films. The $V_{set}$ of the as-grown $MnO_x$ film ranged from 1 to 6.2 V, whereas the $V_{set}$ of the oxygen-annealed film ranged from 2.3 to 3 V. An excess of oxygen in an $MnO_x$ film leads to an increase in $Mn^{4+}$ content at the $MnO_x$ film surface with a subsequent change in the $Mn^{4+}/Mn^{3+}$ ratio at the surface. This was attributed to the change in $Mn^{4+}/Mn^{3+}$ ratios at the $MnO_x$ surface and to grain growth. Oxygen annealing is a possible solution for improving the switching voltage distribution of $MnO_x$ thin films. In addition, crystalline $MnO_x$ can help stabilize the $V_{set}$ and $V_{reset}$ distribution in memory switching in a Ti/$MnO_x$/Pt structure. The improved uniformity was attributed not only to the change of the crystallinity but also to the redox reaction at the interface between Ti and $MnO_x$.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1193-1196
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• 2009

Low resistivity interconnection and high-mobility channel are required to realize ultrahigh-definition LCDs such as 4k ${\times}$ 2k TVs. We evaluated fully Cu-based gate and Source/Drain interconnections, consisting of stacked pure-Cu/Cu-Mn layers for TFT-LCDs, and found the underlying Cu-Mn alloy film has superior adhesion to glass substrates and CVD-SiOx films. It was also confirmed that wet etching of the Cu/Cu-Mn films without residues and low contact resistance with both channel IGZO and pixel ITO films can be obtained. It is thus considered that the stacked Cu/Cu-Mn structure is one of candidates to replacing conventionally pure-Cu/refractory metal.

• 한국세라믹학회지
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• 제37권4호
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• pp.338-344
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• 2000

Grain boundary chemistry and electrical characteristics of polycrystalline BaTiO3 ceramics, which were prepared with sol-gel surface-coated semiconducting powders, were investigated. Mn ions were coated on the powder surface by sol-gel coating-techniques. The additives coated on the surface of the powders were observed to be present near the grain boundaries of the ceramics. The ceramics exhibit the PTCR characteristics with a resistivity jump ratio(Pmax/Pmin) of about 2$\times$103. With raising the temperature from room temprature to 20$0^{\circ}C$, the oxidation state of the Mn ions varied from Mn3+ to Mn2+ in the coating layers. Near the grain boundaries an excessive negative charge layer of about 20nm was formed.

• 공업화학
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• 제32권4호
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• pp.483-486
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• 2021

Catalytic ozonation of methyl ethyl ketone (MEK) has been examined over mesoporous MnO_x/Al₂O₃ (MA) catalysts developed by a solvent deficient method using two different manganese precursors including manganese chloride (C) and manganese sulfate (S) at room temperature. The maximum catalytic activities of MA with C (MEK removal efficiency and ozone decomposition of 98.4 and 93.7%, respectively) were higher than those of MA with S (MEK removal efficiency and ozone decomposition of 96 and 68%, respectively). Also the catalytic stability of MA with C was much higher than that of MA with S. The physico-chemical properties of catalysts are well correlated with the activity results, which confirmed that fine dispersion of MnO_x species with high ratios of Mn³⁺/Mn⁴⁺ and more acid sites are attributed to the higher catalyst stability for the MA-C catalyst.