Influence of Pretreatment Temperature on the Bimetallic Interactions in Pt-Re/Al2O3 Reforming Catalysts Studied by X-Ray Absorption Spectroscopy

Rønning, Magnus; Gjervan, Torbjørn; Prestvik, Rune; Nicholson, D.; Holmén, Anders

doi:10.1006/jcat.2001.3399

Cited by 45 publications

(26 citation statements)

References 43 publications

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“…Our group has previously reported the successful application of sealed quartz capillaries for preserving activated catalysts [10]. In this study, we evaluate and share our experience with other protection methods, namely O 2 and N 2 O passivation, and relate our findings to reports on passivation in the literature.…”

Section: Introductionmentioning

confidence: 84%

“…Sealing in a container under reducing/inert atmosphere after reduction [10] 2. Encapsulation of the reduced metal particles a. by deposition of polyethylene [11][12][13] or 1-butene films [14] on the surface, analogous to the protection of bulk metals against corrosion by coating with polymer films b. by growing a layer of carbon (such as carbon nanofibers or paraffinic wax) around the reduced metal particles [15][16][17] 3.…”

Section: Introductionmentioning

confidence: 99%

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Remarks on the passivation of reduced Cu-, Ni-, Fe-, Co-based catalysts

Huber

Lögdberg

et al. 2006

Catal Lett

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Catalysts containing metals such as Cu, Ni, Fe, Co in their reduced state are often subjected to passivation procedures prior to characterization. Passivation with N 2 O or O 2 to create a protective oxide layer also results in a certain degree of sub-surface oxidation. The heat released during oxidation is a critical parameter. The extent of bulk oxidation depends on the type of oxidant as well as on the size of the metal particles, as shown for copper catalysts. The final, meta-stable passivation layer requires a certain thickness to sustain exposure to ambient atmosphere. The encapsulation of metal particles in carbon is an efficient method for preserving the metallic state, as demonstrated for metallic nickel and iron with carbon nanofibers. The use of passivated samples for characterization of the active, i.e., reduced, catalyst has limited value.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Remarks on the passivation of reduced Cu-, Ni-, Fe-, Co-based catalysts

Huber

Lögdberg

et al. 2006

Catal Lett

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“…In addition, the XRD pattern of the used catalyst was also almost identical to that of the fresh one ( Figure S5). [34,35] As a result, the average valence of the Re species on calcined and reduced ReO x -Pd/CeO 2 was determined to be 7.0 and 3.7, respectively. [34,35] As a result, the average valence of the Re species on calcined and reduced ReO x -Pd/CeO 2 was determined to be 7.0 and 3.7, respectively.…”

Section: Methodsmentioning

confidence: 99%

Hydrodeoxygenation of Vicinal OH Groups over Heterogeneous Rhenium Catalyst Promoted by Palladium and Ceria Support

et al. 2014

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Heterogeneous ReO x -Pd/CeO 2 catalyst showed excellent performance for simultaneous hydrodeoxygenation of vicinal OH groups. High yield (> 99 %), turnover frequency (300 h À1 ), and turnover number (10 000) are achieved in the reaction of 1,4-anhydroerythritol to tetrahydrofuran. This catalyst can be applied to sugar alcohols, and mono-alcohols and diols are obtained in high yields (! 85 %) from substrates with even and odd numbers of OH groups, respectively. The high catalytic performance of ReO x -Pd/CeO 2 can be assigned to rhenium species with + 4 or + 5 valence state, and the formation of this species is promoted by H 2 /Pd and the ceria support.

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“…The average valence of Re was determined by the whiteline area of Re L 3 -edge XANES ( Figures S6 and S7) on the basis of previous reports. [34,35] As a result, the average valence of the Re species on calcined and reduced ReO x -Pd/CeO 2 was determined to be 7.0 and 3.7, respectively. Table 3 and Table S5 list the curve-fitting results of EXAFS (the spectra are shown in Figures S8 and S9).…”

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confidence: 99%