• Title/Summary/Keyword: Cu-Ce catalyst

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A Study on Cu Based Catalysts for Water Gas Shift Reaction to Produce Hydrogen from Waste-Derived Synthesis Gas (폐기물 가스화 합성가스로부터 수소 생산을 위한 수성가스전이 반응용 Cu 기반 촉매 연구)

  • Na, Hyun-Suk;Jeong, Dae-Woon;Jang, Won-Jun;Lee, Yeol-Lim;Roh, Hyun-Seog
    • Transactions of the Korean hydrogen and new energy society
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    • v.25 no.3
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    • pp.227-233
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    • 2014
  • Simulated waste-derived synthesis gas has been tested for hydrogen production through water-gas shift (WGS) reaction over supported Cu catalysts prepared by co-precipitation method. $CeO_2$, $ZrO_2$, MgO, and $Al_2O_3$ were employed as supports for WGS reaction in this study. $Cu-CeO_2$ catalyst exhibited excellent catalytic activity as well as 100% $CO_2$ selectivity for WGS in severe conditions ($GHSV=40,206h^{-1}$ and CO concentration = 38.0%). In addition, $Cu-CeO_2$ catalyst showed stable CO conversion for 20h without detectable catalyst deactivation. The high activity and stability of $Cu-CeO_2$ catalyst are correlated to its easier reducibility, high oxygen mobility/storage capacity of $CeO_2$.

Low Temperature CO Oxidation over CuO Catalyst Supported on Al-Ce Oxide Support (Al-Ce 산화물에 담지된 CuO 촉매상에서 저온 CO산화반응)

  • Park, Jung-Hyun;Yun, Hyun Ki;Shin, Chae-Ho
    • Korean Chemical Engineering Research
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    • v.55 no.2
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    • pp.156-162
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    • 2017
  • CuO(x)/0.3Al-0.7Ce catalysts with different CuO loadings (x = 2~20 wt%) were prepared by impregnation method and investigated the effects of CuO loadings on the low temperature CO oxidation. Of the used catalysts, the CuO(10)/0.3Al-0.7Ce catalyst showed the highest catalytic performance in the absence or presence of water vapor. In the presence of water vapor, the catalytic performance was drastically decreased, with a temperature of 50% CO conversion ($T_{50%}$) shifted to higher temperature by $50^{\circ}C$ compared to the those in dry conditions because of the competitive adsorption of water vapor on the active sites. The copper metal surface area calculated from $N_2O$-titration analysis and the oxygen capacity from CO-pulse experiments were increased with the CuO loadings and showed a maximum at 10 wt%CuO/0.3Al-0.7Ce catalyst. These trends are in good agreement with the tendency of $T_{50%}$ of the catalysts. From these characteristic aspects, it could be deduced that the catalytic performance was closely related to the oxygen capacity and the copper metallic surface area.

Removal of S $O_{2}$ and NO by Dry Sorbent(II) - Efficiency of Cu-Ce and Cu-7Al - (건식법에 의한 이산화황과 산화질소의 제거(II) - Cu-Ce 및 Cu-7Al의 효율 -)

  • 신창섭
    • Journal of Korean Society for Atmospheric Environment
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    • v.9 no.4
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    • pp.288-294
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    • 1993
  • Flue gas control systems for small-scale combustors must be designed to provide highly effective removal of three criteria pollutants (S $O_{2}$, N $O_{x}$ and particulate matter), and must be safe, reliable and small. These requirements make dry, regenerative clean-up process particularly attractive and this paper describes a new concept for integrated pollutant control : a filter comprised of layered, gas permeable membranes that act as an S $O_{2}$ sorbant, a N $O_{x}$ reduction catalyst and a particulate filter. A mixed metal oxide sorbent, Cu-Ce was used as a sorbent/catalyst and the activity was compared with Cu-7Al. The S $O_{2}$ removal eficiency of Cu-Ce was increased with temperature increase up to 500$^{\circ}$C and the catalytic activity for NO was higher than that of Cu-7Al. By the sulfation of Cu-Ce, the reduction activity was increased at the temperature higher than 350$^{\circ}$C. The regeneration of Cu-Ce was very fast and some amount of elemental sulfar was found.

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Development of Cu-CeO2 Catalysts for Selective Oxidation of CO (일산화탄소의 선택적 산화반응을 위한 Cu-CeO2 촉매의 개발)

  • Jung, C.-R.;Han, J.;Yoon, S.P.;Nam, S.-W.;Lim, T.-H.;Hong, S.-A.;Lee, H.-I.
    • Clean Technology
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    • v.8 no.1
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    • pp.53-59
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    • 2002
  • $Cu-CeO_2$ catalysts were prepared by co-precipitation and liquid phase oxidation (CP-LPO) and the prepared catalysts were examined as selective oxidation of carbon monoxide catalysts for the application of fuel cell vehicles. The prepared $Cu-CeO_2$ catalysts showed high reaction activity, but it was hard to find the correlation between the amount of Cu loaded and the reaction activities. As increase of the amount of Cu loaded, the micro pore structure of the catalyst was changed. It is due to the formation of solid solution between Cu and $CeO_2$. During pretreatment, the catalyst formed the solid-solution of Cu-Ce-O, resulting in the improvement of catalytic activity.

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Catalytic Combustion of Benzene over CuO-CeO2 Mixed Oxides Prepared by Co-precipitation Method (침전법으로 제조된 CuO-CeO2 혼합산화물에서 벤젠의 촉매연소반응)

  • Hong, Seong Soo
    • Applied Chemistry for Engineering
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    • v.25 no.3
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    • pp.312-317
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    • 2014
  • Catalytic combustion of benzene over CuO-$CeO_2$ mixed oxides prepared by co-precipitation method were investigated. The CuO-$CeO_2$ mixed oxides were also prepared using different precipitant and CuO precursor. They were characterized by XRD, BET, XPS and $H_2-TPR$. In the CuO-$CeO_2$ catalysts, characteristic copper oxide peaks were shown at $2{\Theta}=35.5^{\circ}$ and $38.5^{\circ}$ regardless of the precipitant. The Cu0.35 catalyst prepared using $NH_4OH$ as a precipitant revealed the highest activity on the combustion of benzene. In addition, the pretreatment with hydrogen enhanced the catalytic activity and the catalyst reduced at $400^{\circ}C$ showed the highest activity on the combustion of benzene.

Effect of Ce Addition on Catalytic Activity of Cu/Mn Catalysts for Water Gas Shift Reaction (수성가스전이반응(Water Gas Shift Reaction)을 위한 Ce 첨가에 따른 Cu/Mn 촉매의 활성 연구)

  • PARK, JI HYE;IM, HYO BEEN;HWANG, RA HYUN;BAEK, JEONG HUN;KOO, KEE YOUNG;YI, KWANG BOK
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.1
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    • pp.1-8
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    • 2017
  • Cu/Mn/Ce catalysts for water gas shift (WGS) reaction were synthesized by urea-nitrate combustion method with the fixed molar ratio of Cu/Mn as 1:4 and 1:1 with the doping concentration of Ce from 0.3 to 0.8 mol%. The prepared catalysts were characterized with SEM, BET, XRD, XPS, $H_2$-TPR, $CO_2$ TPD, $N_2O$ chemisorption analysis. The catalytic activity tests were carried out at a GHSV of $28,000h^{-1}$ and a temperature range of 200 to $400^{\circ}C$. The Cu/Mn(CM) catalysts formed Cu-Mn mixed oxide of spinel structure ($Cu_{1.5}Mn_{1.5}O_4$) and manganese oxides ($MnO_x$). However, when a small amount of Ce was doped, the growth of $Cu_{1.5}Mn_{1.5}O_4$ was inhibited and the degree of Cu dispersion were increased. Also, the doping of Ce on the CM catalyst reduced the reduction temperature and the base site to induce the active site of the catalyst to be exposed on the catalyst surface. From the XPS analysis, it was confirmed that maintaining the oxidation state of Cu appropriately was a main factor in the WGS reaction. Consequently, Ce as support and dopant in the water gas shift reaction catalysts exhibited the enhanced catalytic activities on CM catalysts. We found that proper amount of Ce by preparing catalysts with different Cu/Mn ratios.

A Study on the Characteristics of Ni/Ce0.9Gd0.1O2-x and Cu/Ce0.9Gd0.1O2-x Catalysts for Methanol Steam Reforming Synthesized by Solution Combustion Process (용액연소법으로 합성한 Ni/Ce0.9Gd0.1O2-x와 Cu/Ce0.9Gd0.1O2-x 촉매의 메탄올 수증기 개질 특성 연구)

  • LEE, JUNGHUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.3
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    • pp.209-219
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    • 2019
  • Methanol is a liquid fuel which could also be produced from renewable energy sources and has appreciably high energy density. In this work, we investigated the application of $Ce_{0.9}Gd_{0.1}O_{2-x}$ supported Cu and Ni catalysts for hydrogen production via methanol steam reforming. Catalysts were synthesized by solution combustion synthesis. The prepared catalysts with various active materials and Cu loading amounts were tested in a reactor at $200-300^{\circ}C$, 0-5 barg range and steam to methanol molar ratio was 1.5. The catalytic properties of Cu and Ni were compared, and the catalytic performance was shown to depend on the amounts of metal loading and operating conditions such as reaction temperature and pressure.

The Effect of Nb2O5 on Cu-Nb-CeO2 Catalysts for Water Gas Shift Reaction of Compact Reformer (컴팩트 개질기용 수성가스전이 반응을 위한 Cu-CeO2 촉매에 대한 Nb2O5의 영향)

  • JEONG, CHANG-HOON;KIM, TAE-GWANG;BYON, HUI-JU;KIM, JU-HWAN;BAE, EUN-TAEK;SHEN, KAILIN;JEON, KYUNG-WON;JEONG, DAE-WOON
    • Transactions of the Korean hydrogen and new energy society
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    • v.31 no.1
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    • pp.57-64
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    • 2020
  • The water-gas shift reaction for the compact reformer was carried out at a gas hourly space velocity of 72,152 h-1 over the Cu-Nb-CeO2 catalysts prepared by co-precipitation method. In order to investigate the effect of Nb2O5 promotion over a Cu-CeO2 catalyst, the Nb2O5 loading amount was systematically changed from 0 to 5 wt.%. Among the prepared catalysts, the Cu-Nb-CeO2 (1%) catalyst showed the highest catalytic activity (CO conversion=61% at 400℃) as well as 100% CO2 selectivity. The high activity and stability of Cu-Nb-CeO2 (1%) catalyst are correlated to high Brunauer-Emmett-Teller surface area, small metallic Cu crystallite size, and enhanced redox property.

Study on Catalytic Activity of the Selective CO Oxidation and Characterization Using $La_{0.5}Ce_{0.5}Co_{1-x}Cu_xO_{3-{\alpha}}$ Perovskite Catalysts ($La_{0.5}Ce_{0.5}Co_{1-x}Cu_xO_{3-{\alpha}}$ Perovskite촉매의 선택적 CO 산화반응 및 특성 분석에 관한 연구)

  • Sohn, Jung-Min
    • Transactions of the Korean hydrogen and new energy society
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    • v.18 no.2
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    • pp.116-123
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    • 2007
  • [ $La_{0.5}Ce_{0.5}Co_{1-x}Cu_xO_{3-{\alpha}}$ ](X=0, 0.1, 0.3, 0.5) perovskites were prepared by coprecipitation method at pH 7 or pH 11 and its catalytic activity of selective CO oxidation was investigated. The characteristics of these catalysts were analyzed by $N_2$ adsorption, X-ray diffraction(XRD), SEM, $O_2$-temperature programmed desorption(TPD). The pH value at a preparation step made effect on particle morphology. The smaller particle was obtained with a condition of pH 7. The better catalytic activity was observed using catalysts prepared at pH 7 than pH 11. The maximum CO conversion of 98% was observed over $La_{0.5}Ce_{0.5}Co_{0.7}Cu_{0.3}O_{3-{\alpha}}$ at $320^{\circ}C$. Below $200^{\circ}C$, the most active catalyst was $La_{0.5}Ce_{0.5}Co_{0.9}Cu_{0.1}O_{3-{\alpha}}$, of which conversion was 92% at $200^{\circ}C$. By the substitution of Cu, the evolution of ${\alpha}$-oxygen was remarkably enhanced regardless of pH value at preparation step according to $O_2$-TPD. Among the different ${\alpha}$-oxygen species, the oxygen species evolved between $400^{\circ}C$ and $500^{\circ}C$, gave the better catalytic performance for selective CO oxidation including $La_{0.5}Ce_{0.5}CoO_3$ in which Cu was absent.

Simultaneous Oxidation of NO, CO, and CH4 over Mn-Cu/Al2O3 Catalyst (Mn-Cu/Al2O3 촉매 상에서 NO, CO 및 CH4 동시 산화)

  • Ji Eun Jeong;Chang-Yong Lee
    • Applied Chemistry for Engineering
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    • v.35 no.1
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    • pp.1-7
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    • 2024
  • Mn-M/Al2O3 (M = Cu, Fe, Co, and Ce) catalysts were prepared for simultaneous oxidation of NO, CO, and CH4, and their oxidation activities were compared. The Mn-Cu/ Al2O3 catalyst with the best simultaneous oxidation activity was characterized by XRD, Raman, XPS, and O2-TPD analysis. The result of XRD indicated that Mn and Cu existed as complex oxides in the Mn-Cu/Al2O3 catalyst. Raman and XPS results showed that electron transfer between Mn ions and Cu ions occurred during the formation of the Mn-O-Cu bond in the Mn-Cu/Al2O3 catalyst. The XPS O 1s and O2-TPD analyses showed that the Mn-Cu/Al2O3 catalyst has more adsorbed oxygen species with high mobility than the Mn/Al2O3 catalyst. The high simultaneous oxidation activity of the Mn-Cu/Al2O3 catalyst is attributed to these results. Gas-phase NO promotes the oxidation reactions of CO and CH4 in the Mn-Cu/Al2O3 catalyst while suppressing the NO oxidation reaction. These results were presumed to be because the oxidized NO was used as an oxidizing agent for CO and CH4. On the other hand, the oxidation reactions of CO and CH4 competed on the Mn-Cu/Al2O3 catalyst, but the effect was not noticeable because the catalyst activation temperature was different.