Redox behavior of CeO2–ZrO2 mixed oxides

Vidal, Hilario; Kašpar, Jan; Pijolat, Michèle; Colón, G.; Bernal, S.; Cordon, Ana Maria; Perrichon, V.; Fally, F.

doi:10.1016/s0926-3373(00)00138-7

Cited by 227 publications

(73 citation statements)

References 29 publications

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“…6, two TPR peaks were observed for both GT and CP samples with Ce content of 70-90 mol%, while only the low temperature peak(s) was present for the samples in lower Ce content region. Similar results were reported previously [25,38]. Fornasiero et al…”

Section: Resultssupporting

confidence: 93%

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Hosokawa

Imamura

Iwamoto

et al. 2011

Journal of the European Ceramic Society

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The glycothermal (GT) reaction of Ce acetate and Zr alkoxide directly yielded CeO2-ZrO2 solid solutions in a region of low Ce content ≤40 mol%. Of the CeO2-ZrO2 solid solutions obtained by the GT method and subsequent calcination at 500 or 800 ºC, the sample with 20 mol% Ce content had the largest BET surface area. This sample exhibited the highest Ce-based oxygen release capacity in the whole Ce/Zr composition range.The oxygen release capacities of CeO 2 -ZrO 2 solid solutions synthesized by the GT method were much larger than those of the samples prepared by a coprecipitation (CP) method. The Rietvelt analysis and the repetitive reduction-oxidation experiment indicated that the CeO 2 -ZrO 2 solid solution synthesized by the GT method has a homogeneous structure as compared with that prepared by the CP method.2

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Section: Resultssupporting

confidence: 93%

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Hosokawa

Imamura

Iwamoto

et al. 2011

Journal of the European Ceramic Society

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“…Pure CeO 2 presents two main signals that have been widely described for such oxide. The initial occurrence of the low temperature signal (centered at 470 °C in our case) is due to the surface reduction of Ce 4+ cations into Ce 3+ , while the high temperature signal (with maximum at 754 °C) is associated to Ce 4+ to Ce 3+ reduction in the bulk [8,29,30,56,57].…”

Section: Resultsmentioning

confidence: 57%

“…An inadequate discussion of some nuances in explaining the results of reducibility may result in controversial discussions about the enhancement or detriment of the reducibility in Ce-Zr mixed oxides depending on the loading of Zr, as was pointed out by Vidal et al [56]. Nevertheless, most authors claim a beneficial effect in the ceria reducibility by the addition of Zr because of the increasing of the population of surface Ce 4+ reducible cations, even if the maximum temperature of the low temperature reduction becomes higher than for the pure CeO 2 .…”

Section: Resultsmentioning

confidence: 99%

Synergy between gold and oxygen vacancies in gold supported on Zr-doped ceria catalysts for the CO oxidation

Laguna

Pérez

Centeno

et al. 2015

Applied Catalysis B: Environmental

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“…These peaks are related to the CeO 2 reduction in a solid Ce-ZrO 2 solution, which happened at a lower temperature than the reduction temperature observed for pure CeO 2 . 18 The TPR profile (Figure 2) for the 1.5%Rh/g-Al 2 O 3 catalyst showed a peak at 154 °C, which may be attributed to the reduction of Rh 2 O 3 . 19,20 The profile for the 1.5%Rh/CeO 2 catalyst showed peaks at 96, 224 and 967 °C.…”

Section: Catalyst Characterizationmentioning

confidence: 95%

Partial oxidation of methane to syngas on Rh/Al2O3 and Rh/Ce-ZrO2 catalysts

Oliveira¹,

Bitencourt²,

Passos³

2013

J. Braz. Chem. Soc.

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A oxidação parcial do metano sobre catalisadores de ródio suportados em g-Al 2 O 3 , CeO 2 , ZrO 2 e Ce-ZrO 2 foi investigada. Medidas de DRIFTS (espectroscopia no infravermelho com reflectância difusa) de CO adsorvido mostraram que houve a formação de diferentes espécies de ródio nos diferentes suportes, o que por sua vez influenciou na dispersão do metal. Os efeitos da dispersão metálica e da capacidade de armazenamento de oxigênio sobre a atividade dos catalisadores na oxidação parcial foram discutidos.The partial oxidation of methane with g-Al 2 O 3 -, CeO 2 -, ZrO 2 -and Ce-ZrO 2 -supported rhodium catalysts was investigated. DRIFTS (diffuse reflectance infrared spectroscopy) measurements of adsorbed CO showed the formation of different rhodium species on different supports, which influenced the dispersion of the metal. The effects of the metal dispersion, oxygen storage capacity on the activity of these catalysts for the partial oxidation of methane are discussed.Keywords: methane partial oxidation, methane, ceria-zirconia, rhodium, DRIFTS IntroductionThe catalytic partial oxidation of methane is an alternative to steam reforming, the industrial process for the production of synthesis gas from methane. Partial oxidation is a more energy efficient and less expensive process than steam reforming. The partial oxidation of methane (POM) is a mildly exothermic reaction, in which methane reacts with a limited amount of oxygen to produce hydrogen and carbon monoxide:The POM process is capable of producing syngas with a H 2 /CO ratio of approximately 2, which makes it a favorable method for methanol and hydrocarbon synthesis. 1,2 Noble metal catalysts (Ir, Ru, Rh, Pt, Pd) exhibit high activity, along with long-term stability, while minimizing the levels of coking, particularly when compared to the non-noble metals (such as Fe, Co, Ni). 1,2 The lack of a hydrogen infrastructure, as well as disadvantages in hydrogen storage, has stimulated the development of compact fuel processors, which are able to produce a rich hydrogen gas mixture from hydrocarbons. Several studies have reported that Rh catalysts are especially appropriate for use in compact fuel processors because of their high activity, selectivity for syngas and resistance to carbon deposition. 2 One of the main disadvantages of methane conversion is the deactivation due to coke formation. Thus, there is a great interest in designing catalysts that minimize the deleterious effect of coking. The presence of oxygen vacancies in supports that contain CeO 2 proved to be instrumental in keeping the metal particles free from coke deposition during the steam reforming, 3-5 partial oxidation, 6-9 CO 2 reforming and autothermal reforming of methane, 10-12 when using nickel or noble metals as catalysts. [13][14][15] Furthermore, ceria may also improve the catalytic performance by increasing the noble metal dispersion and stabilizing the support. Both the metal dispersion and support reducibility of Pt/CeO 2 and Pt/Ce x Zr 1-x O 2 were found to influence the catalytic ...

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Redox behavior of CeO2–ZrO2 mixed oxides

Cited by 227 publications

References 29 publications

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

Synergy between gold and oxygen vacancies in gold supported on Zr-doped ceria catalysts for the CO oxidation

Partial oxidation of methane to syngas on Rh/Al2O3 and Rh/Ce-ZrO2 catalysts

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