Use of methanol as an IR molecular probe to study the surface of polycrystalline ceria

Badri, Ahmed; Binet, Claude; Lavalley, Jean‐Claude

doi:10.1039/a606628c

Cited by 144 publications

(155 citation statements)

References 49 publications

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“…The spectrum showed a v(OC) band centered around 10611150 cm ¹1 assigned to methoxy species dissociated on the coordinatively unsaturated CeO (Lewis acidbase pair) site. 25 Considering the result that a negative band at 1632 cm ¹1 due to adsorbed water was also observed after the introduction of methanol, the results indicated that water coordinated to a Ce 4+ cation (Lewis acid site) was replaced by methoxy species. This suggests that the Ce 4+ cations on CeO 2 can act as Lewis acid even in the presence of water in the first coordination sphere.…”

Section: ¹1mentioning

confidence: 99%

“…The nature of acidbase pair sites was studied by methanol adsorption experiments with IR. The IR study by Lavalley et al 25 established a model for the dissociative adsorption of methanol on the acidbase pair site of dehydrated CeO 2 . Since we conducted the catalytic studies without pre-dehydration of CeO 2 , we carried out methanol adsorption IR experiments of untreated CeO 2 .…”

Section: ¹1mentioning

confidence: 99%

“…The amount of the surface CeO sites can be estimated by the IR experiment using the absorption coefficient of the methoxy species. 25 To examine the correlation between the amount of the CeO sites and the reaction rate, we prepared various CeO 2 samples and measured their activity for transamidation as well as the amount of the methoxy species on CeO 2 by IR experiments. For a series of CeO 2 catalysts, there was a good linearity between the reaction rate and amount of methoxy species.…”

Section: ¹1mentioning

confidence: 99%

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CeO2-catalyzed Transformations of Nitriles and Amides

2012

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Recently, cerium oxides have been extensively used as heterogeneous catalysts for green organic reactions. This review describes recent progress in such reactions, with a focus on our studies on pure CeO 2 -catalyzed reactions of nitriles and amides with nucleophiles (H 2 O, alcohols, and amines). Hydration of nitriles to amides in water, one-pot ester synthesis from nitriles and alcohols, one-pot synthesis of N-alkylamides from nitriles with amines, and synthesis of N-alkylamides from amides and amines (transamidation) are selectively catalyzed by CeO 2 under aqueous or solvent-free conditions. Mechanistic studies suggest that a cooperation of Lewis acid site (Ce 4+ cation) and acidbase (CeO) pair site plays essential roles in the catalytic reactions.

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Section: ¹1mentioning

confidence: 99%

Section: ¹1mentioning

confidence: 99%

Section: ¹1mentioning

confidence: 99%

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CeO2-catalyzed Transformations of Nitriles and Amides

2012

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“…Spectra of Gapromoted catalysts present some differences depending on the Ga-content (Fig. 3, spectra bd [53] are not observed in any sample, suggesting that gallium is mainly incorporated in the framework of crystalline phases.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Preparation, characterization and catalytic behavior for propane partial oxidation of Ga-promoted MoVTeO catalysts

Hernández-Morejudo

Massó

García-González

et al. 2015

Applied Catalysis A: General

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ElsevierHernández Morejudo, S.; Masso Ramírez, A.; García-González, E.; Concepción Heydorn, P.; López Nieto, JM. (2015). Preparation, characterization and catalytic behavior for propanepartial oxidation of Ga-promoted MoVTeO catalysts. Applied Catalysis A: General. 504:51-61. doi:10.1016/j.apcata.2014.12.039. The results showed that the addition of small amount of gallium significantly increase the selectivity to acrylic acid (AA) at low propane conversion. However, at high propane conversion, the selectivity to AA strongly depends on both the catalyst composition and the gallium incorporation method. The higher selectivity to acrylic acid over Ga-containing MoVTeO catalysts has been related to: i) structural changes in the M1 phase by the incorporation of Ga 3+ into the octahedral structural framework, and/or ii) incorporation of Ga 3+ species on the catalyst surface thus modifying catalysts acid properties.

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“…The latter species have been characterized by infrared reflection-absorption spectroscopy (IRAS) as on top, doubly bridged, and triply bridged entities with respect to the Ce cations [19,[22][23][24]. The surface methoxy species are quite stable and decompose at temperatures above 550 K to yield H 2 , CO, H 2 O, and formaldehyde (FA).…”

Section: Introductionmentioning

confidence: 99%

Methanol Reactivity on Silica-Supported Ceria Nanoparticles

2014

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Ceria (CeO 2 ) has been used in a number of catalytic processes, either as a support or promoter. For a better understanding of the factors that control the reactivity of ceria, we have used well-ordered CeO 2 (111) films and ceria nanoparticles supported on an ordered SiO 2 film, as model catalysts. The systems were examined in the dehydrogenation of methanol to formaldehyde as a test reaction by using the techniques of infrared spectroscopy and temperature programmed desorption. The results revealed low-temperature reactivity (below 450 K) for supported ceria particles that is not present on ordered films, which show reactivity at 565 K. The results indicate that low-coordinated sites play an important role in the methanol reactivity on ceria.

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Use of methanol as an IR molecular probe to study the surface of polycrystalline ceria

Cited by 144 publications

References 49 publications

CeO2-catalyzed Transformations of Nitriles and Amides

CeO2-catalyzed Transformations of Nitriles and Amides

Preparation, characterization and catalytic behavior for propane partial oxidation of Ga-promoted MoVTeO catalysts

Methanol Reactivity on Silica-Supported Ceria Nanoparticles

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