• Title/Summary/Keyword: Cu-catalyst

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Enhanced Catalytic Activity of Cu/ZnO/Al2O3 Catalyst by Mg Addition for Water Gas Shift Reaction (Mg 첨가에 따른 수성가스전이반응용 Cu/ZnO/Al2O3 촉매의 활성 연구)

  • Park, Ji Hye;Baek, Jeong Hun;Hwang, Ra Hyun;Yi, Kwang Bok
    • Clean Technology
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    • v.23 no.4
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    • pp.429-434
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    • 2017
  • To investigate the effect of magnesium oxide addition, $Cu/ZnO/MgO/Al_2O_3$ (CZMA) catalysts were prepared using co-precipitation method with fixed molar ratio of Cu/Zn/Mg/Al as 45/45/5/5 mol% for low-temperature water gas shift reaction. Synthesized catalysts were characterized by using BET, $N_2O$ chemisorption, XRD, $H_2-TPR$ and $NH_3-TPD$ analysis. The catalytic activity tests were carried out at a GHSV of $28,000h^{-1}$ and a temperature range of $200{\sim}320^{\circ}C$. At the same condition, magnesium oxide added catalyst (CZMA 400) showed that the lowest reduction temperature and stable presence of $Cu^+$, that is active species and abundant weak acid site. Also magnesium oxide added catalysts (CZMA) showed higher catalytic activity at temperature range above $240^{\circ}C$ than the catalyst without magnesium oxide (CZA). Consequently, CZMA 400 catalyst is considered to be excellent catalyst showing CO conversion of 77.59% without deactivation for about 75 hours at $240^{\circ}C$, GHSV $28,000h^{-1}$.

Characteristics of SnO2 Thick Film Gas Sensors Doped with Catalyst (촉매가 첨가된 SnO2 후막형 가스센서의 특성 연구)

  • Lee, Don-Kyu;Yu, Yoon-Sick;Lee, Ji-Young;Yu, Il
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.8
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    • pp.622-626
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    • 2010
  • Cu doped $SnO_2$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and annealed at $500^{\circ}C$ in air, respectively. Structural properties of $SnO_2$ by X-ray diffraction showed (110), (101) and (211) dominant tetragonal phase. The effects of catalyst Cu in $SnO_2$-based gas sensors were investigated. Sensitivity of $SnO_2$:Cu sensors to 2,000 ppm $CO_2$ gas and 50 ppm $H_2S$ gas was investigated for various Cu concentration. The highest sensitivity to $CO_2$ gas and $H_2S$ gas of Cu doped $SnO_2$ gas sensors was observed at the 8 wt% and 12 wt% Cu concentration, respectively. The improved sensitivity in the Cu doped $SnO_2$ gas sensors was explained by decrease of electron depletion region in Cu and $SnO_2$ junction, and increase of reactive oxygen and surface area in the $SnO_2$.

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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An Optimization of Aging Time for Low-Temperature Water-Gas Shift Over Cu-Zn-Al Catalyst (저온 수성가스 전이 반응용 Cu-Zn-Al 촉매의 숙성시간 최적화)

  • SHIM, JAE-OH;NA, HYUN-SUK;AHN, SEON-YONG;JANG, WON-JUN;ROH, HYUN-SEOG
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.2
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    • pp.103-110
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    • 2019
  • Cu-Zn-Al catalysts were prepared via co-precipitation method for low-temperature water-gas shift (LT-WGS) reaction under practical reaction condition. Aging time was systematically changed to find optimum point for LT-WGS under practical condition. The Cu-Zn-Al catalyst aged for 72 hours showed the highest CO conversion within low-temperature range as well as very stable catalytic activity for 200 hours despite the practical reaction condition.

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.

Effects of Base Metal on the Partial Oxidation of Methane Reaction (메탄의 부분산화반응에 미치는 Base metal의 영향)

  • 오영삼;장보혁;백영순;이재의;목영일
    • Journal of Energy Engineering
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    • v.8 no.2
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    • pp.256-264
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    • 1999
  • The performance of the Pt-B/cordierite catalysts (2 wt%) Pt, 70 wt% Alumina, 28 wt%) Ceria and Zirconia, B: base metal) loaded with 6∼12 wt% Mn, Cu, V, Co, Cr and Ba, respectively was studied for partial oxidation of methane reaction and compared with that of Ni loaded catalyst. As a results, it was found that Ba, Co, Cr as well as Ni loaded catalysts showed higher activity for methane partial oxidation of methane than the Mn, Cu and V loaded catalyst. But it was known that catalysts having good activity for methane showed the good activity for coke formation, too. A XRD analysis of the catalyst before and after the reaction using 5 wt% Ni/Al$_2$O$_3$) showed that there were three Ni phases. In these results, it was found that methane oxidation reaction occulted at the front of the catalyst bed consisted of NiAl$_2$O$_4$and NiO and reforming reaction occurred at the rear part of the catalyst bed consisted of reduced Ni.

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The effects of conductivity and CNT cathode on electricity generation in air-cathode microbial fuel cell (공기양극 미생물연료전지 시스템에서 전력발생특성에 미치는 전기전도도와 CNT 양극의 영향)

  • Yoo, Kyu-Seon;Park, Hyun-Soo;Song, Young-Chae;Woo, Jung-Hui;Lee, Chae-Young;Chung, Jae-Woo
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.3
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    • pp.355-360
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    • 2012
  • The characteristics of power generation were investigated by changing the electrical conductivity from 10 to 40mS/cm using air-cathode microbial fuel cell, which had graphite fiber fabric(GFF) anode. There were three kinds of cathode used: one was carbon cloth cathode coated with Pt, another was carbon nanotube(CNT) cathode with non-precious catalyst of Fe-Cu-Mn, and the other was carbon nanotube(CNT) cathode without any catalyst. When it was operated in batch mode, power density of 1369.5mW/$m^2$ was achieved at conductivity of 20mS/cm. Power density from MFC with CNT cathode coated with multi-catalyst of Fe-Cu-Mn was shown about 985.55mW/$m^2$, which was 75.1% compared the power density of carbon cloth coated with Pt. This meant that CNT cathode coated with multi-catalyst of Fe-Cu-Mn could be an alternative of carbon cloth cathode.

1,4-Dioxane Decomposition by Catalytic Wet Peroxide Oxidation using Cu Wire Catalysts (Cu wire 촉매를 이용한 촉매습식과산화공정에 의한 1,4-다이옥산의 분해)

  • Lee, Dong-Keun;Kim, Dul Sun
    • Clean Technology
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    • v.22 no.4
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    • pp.281-285
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    • 2016
  • Cu wire catalyst was highly reactive toward catalytic wet peroxide oxidation of the highly refractory 1,4-dioxane. While complete removal of 1,4-dioxane could be achieved with the catalyst, the removed 1,4-dioxane could not totally mineralized into $CO_2$ and $H_2O$. In accordance with the disappearance of 1,4-dioxane, formaldehyde and oxalic acid were formed gradually with reaction time and they went through maxima. At around the time of maximum concentrations of these two intermediates acetaldehyde concentration was increased drastically and showed maximum value. With the disappearance of these three intermediates, formic acid together with ethylene glycol diformate began to increase gradually. The Cu wire catalyst was proved also to be highly stable against deactivation during the reaction.

Effects of Cu and K Addition on Catalytic Activity for Fe-based Fischer-Tropsch Reaction (Fe계 Fischer-Tropsch 반응에서 촉매활성에 대한 Cu와 K의 첨가 효과)

  • Lee, Chan Yong;Kim, Eui Yong
    • Clean Technology
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    • v.25 no.1
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    • pp.1-6
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    • 2019
  • Effects of the Cu and K addition and the reduction condition of Fe-based catalysts for Fischer-Tropsch reaction are studied in a continuous flow reactor in this research. The catalysts for the reaction were prepared by homogeneous precipitation followed by incipient wetness impregnation. Physicochemical properties of the $Al_2O_3$ supported Fe-based catalysts are characterized by various methods including X-ray diffraction (XRD), temperature programmed reduction (TPR), and scanning electron microscopy (SEM). Catalytic activities and stabilities of the Fe/Cu/K catalyst are investigated in time-on-stream for an extended reaction time over 216 h. It is found that a reduction of the catalysts using a mixture of CO and $H_2$ can promote their catalytic activities, attributed to the iron carbides formed on the catalysts surface by X-ray diffraction analysis. The addition of Cu induces a fast stabilization of the reaction reducing the time to reach at the steady state by enhancement of catalytic reduction. The addition of K to the catalysts increases the CO conversion, while the physical stability of catalyst decreases with potassium loading up to 5%. The Fe/Cu (5%)/K (1%) catalyst shows an enhanced long term stability for the Fischer-Tropsch reaction under the practical reaction condition, displaying about 15% decrease in the CO conversion after 120 h of the operation.

The effect of the modification methods on the catalytic performance of activated carbon supported CuO-ZnO catalysts

  • Duan, Huamei;Yang, Yunxia;Patel, Jim;Burke, Nick;Zhai, Yuchun;Webley, Paul A.;Chen, Dengfu;Long, Mujun
    • Carbon letters
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    • v.25
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    • pp.33-42
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    • 2018
  • Activated carbon (AC) was modified by ammonium persulphate or nitric acid, respectively. AC and the modified materials were used as catalyst supports. The oxygen groups were introduced in the supports during the modifications. All the supports were characterized by $N_2$-physisorption, Raman, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and thermogravimetric analysis. Methanol synthesis catalysts were prepared through wet impregnation of copper nitrate and zinc nitrate on the supports followed by thermal decomposition. These catalysts were measured by the means of $N_2$-physisorption, X-ray diffraction, XPS, temperature programmed reduction and TEM tests. The catalytic performances of the prepared catalysts were compared with a commercial catalyst (CZA) in this work. The results showed that the methanol production rate of AC-CZ ($23mmol-CH_3OH/(g-Cu{\cdot}h)$) was higher, on Cu loading basis, than that of CZA ($9mmol-CH_3OH/(g-Cu{\cdot}h)$). We also found that the modification methods produced strong metal-support interactions leading to poor catalytic performance. AC without any modification can prompt the catalytic performance of the resulted catalyst.