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Structural and kinetic study of the reduction of CuO-CeO2/Al2O3 by time-resolved X-ray diffraction

Vladimir Galvita (UGent) , Hilde Poelman (UGent) , Guy Marin (UGent) , Christophe Detavernier (UGent) , Geert Rampelberg (UGent) and Bob De Schutter (UGent)
(2012) CATALYSIS LETTERS. 142(8). p.959-968
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Abstract
The crystallographic structure of (11 wt.%)CuO-(6 wt.%)CeO2/gamma-Al2O3 has been studied and compared with (11 wt.%)CuO/gamma-Al2O3 under reducing conditions, using time-resolved in situ X-ray diffraction in the temperature range 25-800 A degrees C. In CuO-CeO2/Al2O3, H-2-TPR reduces the CuO phase to Cu, while in C3H8-TPR reduction follows a two-step pathway via Cu2O. A thermal treatment in He also induces reduction for CuO, albeit at higher temperature. In addition to CuO reduction, the CeO2 promoter in CuO-CeO2/Al2O3 is also partially reduced, without crystallographic transition, regardless of the atmosphere and at similar temperature where reduction of CuO occurs. Supported CuO as in CuO-CeO2/Al2O3 or CuO/Al2O3, is more readily reduced by thermal treatment in He than unsupported CuO and Cu2O. Moreover, the addition of CeO2 to the CuO-CeO2/Al2O3 catalyst allows for enhanced reducibility of CuO, compared to CuO/Al2O3. The CuO phase in CuO-CeO2/Al2O3 is reduced to Cu2O and partly to Cu at 700 A degrees C and mainly to Cu at 800 A degrees C in He flow. The thermal reduction of CuO-CeO2/Al2O3 requires an apparent activation energy of 216 kJ/mol. An isothermal reduction treatment at 800 C-o in He reduces CuO-CeO2/Al2O3, as demonstrated by time-resolved in situ X-ray diffraction. Supported CuO are more easily reduced by thermal treatment compared to unsupported CuO and Cu2O. The CuO phase in CuO-CeO2/Al2O3 is reduced to Cu2O and partly to Cu at 700 A degrees C and mainly to Cu at 800 A degrees C in He flow (see figure).
Keywords
Time-resolved in situ XRD, Structural investigation, CuO-CeO2/Al2O3, Hydrogen and propane reduction, Thermal reduction, Supported metal oxides, THERMAL REDUCTION, REDOX PROPERTIES, TOTAL OXIDATION, COPPER OXIDES, CO OXIDATION, RE-OXIDATION, CATALYSTS, OXYGEN, COMBUSTION, PROPANE

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Citation

Please use this url to cite or link to this publication:

Chicago
Galvita, Vladimir, Hilde Poelman, Guy Marin, Christophe Detavernier, Geert Rampelberg, and Bob De Schutter. 2012. “Structural and Kinetic Study of the Reduction of CuO-CeO2/Al2O3 by Time-resolved X-ray Diffraction.” Catalysis Letters 142 (8): 959–968.
APA
Galvita, V., Poelman, H., Marin, G., Detavernier, C., Rampelberg, G., & De Schutter, B. (2012). Structural and kinetic study of the reduction of CuO-CeO2/Al2O3 by time-resolved X-ray diffraction. CATALYSIS LETTERS, 142(8), 959–968.
Vancouver
1.
Galvita V, Poelman H, Marin G, Detavernier C, Rampelberg G, De Schutter B. Structural and kinetic study of the reduction of CuO-CeO2/Al2O3 by time-resolved X-ray diffraction. CATALYSIS LETTERS. 2012;142(8):959–68.
MLA
Galvita, Vladimir, Hilde Poelman, Guy Marin, et al. “Structural and Kinetic Study of the Reduction of CuO-CeO2/Al2O3 by Time-resolved X-ray Diffraction.” CATALYSIS LETTERS 142.8 (2012): 959–968. Print.
@article{2969132,
  abstract     = {The crystallographic structure of (11 wt.%)CuO-(6 wt.%)CeO2/gamma-Al2O3 has been studied and compared with (11 wt.%)CuO/gamma-Al2O3 under reducing conditions, using time-resolved in situ X-ray diffraction in the temperature range 25-800 A degrees C. In CuO-CeO2/Al2O3, H-2-TPR reduces the CuO phase to Cu, while in C3H8-TPR reduction follows a two-step pathway via Cu2O. A thermal treatment in He also induces reduction for CuO, albeit at higher temperature. In addition to CuO reduction, the CeO2 promoter in CuO-CeO2/Al2O3 is also partially reduced, without crystallographic transition, regardless of the atmosphere and at similar temperature where reduction of CuO occurs. Supported CuO as in CuO-CeO2/Al2O3 or CuO/Al2O3, is more readily reduced by thermal treatment in He than unsupported CuO and Cu2O. Moreover, the addition of CeO2 to the CuO-CeO2/Al2O3 catalyst allows for enhanced reducibility of CuO, compared to CuO/Al2O3. The CuO phase in CuO-CeO2/Al2O3 is reduced to Cu2O and partly to Cu at 700 A degrees C and mainly to Cu at 800 A degrees C in He flow. The thermal reduction of CuO-CeO2/Al2O3 requires an apparent activation energy of 216 kJ/mol.
An isothermal reduction treatment at 800 C-o in He reduces CuO-CeO2/Al2O3, as demonstrated by time-resolved in situ X-ray diffraction. Supported CuO are more easily reduced by thermal treatment compared to unsupported CuO and Cu2O. The CuO phase in CuO-CeO2/Al2O3 is reduced to Cu2O and partly to Cu at 700 A degrees C and mainly to Cu at 800 A degrees C in He flow (see figure).},
  author       = {Galvita, Vladimir and Poelman, Hilde and Marin, Guy and Detavernier, Christophe and Rampelberg, Geert and De Schutter, Bob},
  issn         = {1011-372X},
  journal      = {CATALYSIS LETTERS},
  keywords     = {Time-resolved in situ XRD,Structural investigation,CuO-CeO2/Al2O3,Hydrogen and propane reduction,Thermal reduction,Supported metal oxides,THERMAL REDUCTION,REDOX PROPERTIES,TOTAL OXIDATION,COPPER OXIDES,CO OXIDATION,RE-OXIDATION,CATALYSTS,OXYGEN,COMBUSTION,PROPANE},
  language     = {eng},
  number       = {8},
  pages        = {959--968},
  title        = {Structural and kinetic study of the reduction of CuO-CeO2/Al2O3 by time-resolved X-ray diffraction},
  url          = {http://dx.doi.org/10.1007/s10562-012-0859-4},
  volume       = {142},
  year         = {2012},
}

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