Preferential oxidation of CO in excess H2 over CuO/CeO2 catalysts: Characterization and performance as a function of the exposed face present in the CeO2 support

Gamarra, Daniel; Cámara, Antonio López; Monte, Manuel J.S.; Rasmussen, Søren Birk; Chinchilla, Lidia E.; Hungría, Ana B.; Munuera, G.; Győrffy, Nóra; Schay, Z.; Corberán, V. Cortés; Conesa, J.C.; Martı́nez-Arias, A.

doi:10.1016/j.apcatb.2012.11.008

Cited by 157 publications

(130 citation statements)

References 75 publications

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“…Cerium dioxide is well known because of its redox properties 35 allowing easy transitions between oxidized and reduced states, depending on the external conditions. Oxygen storage capacity makes ceria suitable for several applications such as those in automotive three way catalysts [5][6][7] and, in general, in oxidation catalysis [8][9][10][11][12][13] . Cerium dioxide is also used as sensor 14,15 , in fuel 40 cell technology as a solid state electrolyte 16,17 , and even in cosmetics 18 .…”

Section: Introductionmentioning

confidence: 99%

The interaction of oxygen with the surface of CeO₂–TiO₂mixed systems: an example of fully reversible surface-to-molecule electron transfer

Gionco

Giamello

Mino

et al. 2014

Phys. Chem. Chem. Phys.

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Mixed CeO 2 -TiO 2 systems have been synthesized using the sol-gel technique in a symmetric range of 5 nominal compositions (0.1, 0.5, 0.9 CeO 2 molar fraction respectively). The solid materials have been characterised using a variety of diffractometric and spectroscopic techniques. The intimate contact between the two components during the synthesis leads to heterogeneous systems which are based on the presence, beside the two individual oxide phases, of a mixed phase of a cerium titanate (Ce 2 Ti 2 O 7 , pyrochlore structure) which contains Ce 3+ ions imparting particular optical properties to the solid 10 (pronounced red shift with respect to the band gap transition of the two oxides). Ce 3+ ions are present at the surface of the systems together with tetravalent Ce and Ti ions. The mixed solids can be reduced by annealing under vacuum and, upon reoxidation in mild conditions with O 2 , form superoxide species adsorbed on Ce 4+ which have, as already reported for low loading CeO 2 -TiO 2 systems, peculiar spectroscopic properties with respect to superoxide adsorbed on bare cerium dioxide.

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Section: Introductionmentioning

confidence: 99%

The interaction of oxygen with the surface of CeO₂–TiO₂mixed systems: an example of fully reversible surface-to-molecule electron transfer

Gionco

Giamello

Mino

et al. 2014

Phys. Chem. Chem. Phys.

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“…Nevertheless, although reaction models for CO oxidation (competing or not with H 2 oxidation, as it occurs under CO-PROX conditions) have been proposed on the basis of indirect analysis of redox or catalytic properties for this type of catalyst [38,39]; direct evidence on redox changes taking place in the catalyst under the reactant atmosphere, which could provide details on the nature of active sites for the processes taking place under CO-PROX conditions in this type of catalyst, has, to the best of our knowledge, only recently been reported in a series of contributions from our laboratory [18,40,41]. In turn, such redox characteristics have been shown recently to depend strongly on the type of face exposed by the ceria support, which has important consequences for the CO-PROX performance of this type of catalyst [42].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Active Sites/Entities and Redox/Catalytic Correlations in Copper-Ceria-Based Catalysts for Preferential Oxidation of CO in H2-Rich Streams

et al. 2013

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This article reviews work done at authors' laboratories about catalysts based on combinations between copper and ceria for preferential oxidation of CO in H 2 -rich streams (CO-PROX). The main focus of this review is the characterization of active sites for the process on the basis of spectroscopic analysis of the systems under reaction conditions (operando techniques). On such a basis, it is exposed the state of the art in this field in connection with results obtained in other laboratories. OPEN ACCESSCatalysts 2013, 3 379 Keywords: copper-ceria catalysts; CO preferential oxidation (CO-PROX); diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS); X-ray absorption near edge spectroscopy (XANES); Raman; X-ray diffraction (XRD); X-ray photoelectron spectroscopy (XPS)

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“…Their performances are mainly attributed to the synergistic redox properties of the copper-ceria interfacial sites [12][13][14][15][16][17][18]. In the preferential oxidation of carbon monoxide, the presence of oxygen vacancy defects (OVDs) and other lattice defects can play a very important role in the surface reactivity [18].…”

Section: Introductionmentioning

confidence: 99%

Preferential CO oxidation (CO-PROX) catalyzed by CuO supported on nanocrystalline CeO2 prepared by a freeze-drying method

Arango-Díaz

Moretti

Talon

et al. 2014

Applied Catalysis A: General

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a b s t r a c tNanocrystalline CeO 2 with a regular size of 9.5 nm was prepared by a freeze-drying method, and subsequent impregnated with a Cu(II) acetate solution, varying the loading of Cu (3, 6, 12 wt.%). The resulting CuO/CeO 2 materials were characterized by N 2 physisorption at −196 • C, HRTEM, H 2 -TPR, X-ray diffraction, Raman spectroscopy and XPS and tested as catalysts in the preferential CO oxidation in a H 2 -rich stream (CO-PROX) in the temperature range • C. In spite of their low specific surface areas the catalysts exhibited a good catalytic performance, resulting active and selective in the CO-PROX reaction at low temperatures. The inhibiting effect of the simultaneous presence of CO 2 (15 vol.%) and H 2 O (10 vol.%) in the reaction mixture on the performance of CuO-CeO 2 catalysts was also investigated. The addition of CO 2 and water in the gas stream depressed CO oxidation up to 160• C, its effect being negligible at higher temperatures. Nevertheless, despite these expected deactivation phenomena, a CO conversion value higher than 90% and a CO 2 selectivity of about 90% was achieved for all the samples at 160• C. The excellent performance, especially shown by the catalyst with 6 wt%. of copper, has been related to the wide dispersion of the copper active sites associated with the high amount of Ce 4+ species before reaction.

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Preferential oxidation of CO in excess H2 over CuO/CeO2 catalysts: Characterization and performance as a function of the exposed face present in the CeO2 support

Cited by 157 publications

References 75 publications

The interaction of oxygen with the surface of CeO₂–TiO₂mixed systems: an example of fully reversible surface-to-molecule electron transfer

The interaction of oxygen with the surface of CeO₂–TiO₂mixed systems: an example of fully reversible surface-to-molecule electron transfer

Characterization of Active Sites/Entities and Redox/Catalytic Correlations in Copper-Ceria-Based Catalysts for Preferential Oxidation of CO in H2-Rich Streams

Preferential CO oxidation (CO-PROX) catalyzed by CuO supported on nanocrystalline CeO2 prepared by a freeze-drying method

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Preferential oxidation of CO in excess H2 over CuO/CeO2 catalysts: Characterization and performance as a function of the exposed face present in the CeO2 support

Cited by 157 publications

References 75 publications

The interaction of oxygen with the surface of CeO2–TiO2mixed systems: an example of fully reversible surface-to-molecule electron transfer

The interaction of oxygen with the surface of CeO2–TiO2mixed systems: an example of fully reversible surface-to-molecule electron transfer

Characterization of Active Sites/Entities and Redox/Catalytic Correlations in Copper-Ceria-Based Catalysts for Preferential Oxidation of CO in H2-Rich Streams

Preferential CO oxidation (CO-PROX) catalyzed by CuO supported on nanocrystalline CeO2 prepared by a freeze-drying method

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The interaction of oxygen with the surface of CeO₂–TiO₂mixed systems: an example of fully reversible surface-to-molecule electron transfer

The interaction of oxygen with the surface of CeO₂–TiO₂mixed systems: an example of fully reversible surface-to-molecule electron transfer