Alumina-Supported Vanadium Oxide in the Dehydrogenation of Butanes

Harlin, M.E.; Niemi, V.; Krause, A.O.I.

doi:10.1006/jcat.2000.2969

Cited by 109 publications

(91 citation statements)

References 24 publications

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“…From our in situ investigations, it is clear that reduced vanadium is active in the dehydrogenation of nbutane and as shown in figure 11, however complete reduction to V 3+ is not beneficial, as neighbouring V 3+ sites will bond adsorbates of C-deposits too strongly. This is in agreement with the work of Harlin et al [36] who concluded that reduced vanadium was indeed active in the dehydrogenation reaction. By co-feeding oxygen, a higher oxidation state of vanadium is maintained.…”

Section: N-butane Dehydrogenation On V Based Catalystssupporting

confidence: 93%

“…Since deactivation occurred at much slower rate at this low pressure, additional information can be gleamed from the "slow-mo" view of catalyst activity. Benzene has been detected as a minor product in a high pressure study of vanadium oxide/alumina catalysts for butane dehydrogenation [36], can form via the hydrogenolysis of the secondary-secondary C-C bond followed by oligomerization to benzene. Several authors have investigated zeolite based catalysts for the aromatisation of nbutane to benzene [41][42][43].…”

Section: N-butane Dehydrogenation On V Based Catalystsmentioning

confidence: 99%

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The role of carbon species in heterogeneous catalytic processes: an in situ soft x-ray photoelectron spectroscopy study

Vass

Hävecker

Zafeiratos

et al. 2008

J. Phys.: Condens. Matter

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High pressure X-ray photoelectron spectroscopy (XPS) is used to characterize heterogeneous catalytic processes. The success of the new technique based on the possibility to correlate the catalytic activity and the electronic structure of an active surface. The dynamic character of a catalyst surface can be demonstrated impressively by this technique. In this contribution the basics of high pressure XPS will be discussed. Three examples of heterogeneous catalytic reactions are presented in this contribution. The selective hydrogenation of 1-pentyne over Pd based catalysts and the dehydrogenation of n-butane and the oxidation of ethylene over V based catalysts. It is shown, that the formation of subsurface carbons plays an important role in all the examples. The incorporated carbon changes the electronic structure of the surface and so controls the selectivity of the reaction. A change of the educts in the reaction atmosphere induces modifications of the electronic surface structure of the operation catalysts.

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Section: N-butane Dehydrogenation On V Based Catalystssupporting

confidence: 93%

Section: N-butane Dehydrogenation On V Based Catalystsmentioning

confidence: 99%

The role of carbon species in heterogeneous catalytic processes: an in situ soft x-ray photoelectron spectroscopy study

Vass

Hävecker

Zafeiratos

et al. 2008

J. Phys.: Condens. Matter

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show abstract

“…and V 3? oxidation states produced by preliminary reduction with H 2 , CH 4 and CO [40]. The rate of oxidation of toluene and selectivity for benzaldehyde formation with mixed V 2 O 5 -WO 3 catalysts was found [41] .…”

Section: Alohmentioning

confidence: 91%

XPS–SIMS Surface Characterization of Aluminovanadate Oxide Catalyst Precursors Co-Precipitated at Different pH: Effect of Calcination

2012

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X-ray photoelectron spectroscopy and time-offlight secondary ion mass spectrometry were employed in a comparative study of the surface physical and chemical state of aluminovanadate oxide catalyst precursors (V-Al-O), which were precipitated in the range of pH from 5.5 to 10, after drying and calcination. Core-level photoelectron spectra, X-ray induced Auger and valence band spectra of the samples were measured so as to quantitatively evaluate the surface concentrations of the catalyst components. The binding energy shifts of the respective O 1s, V 2p and Al 2p lines were determined as a function of pH and analyzed in terms of the initial state effect related to the atomic charge and Madelung potential. The surface of the catalysts was composed of aluminum hydroxide/oxyhydroxide and of dispersed vanadium oxide species. Increasing pH was found to result in a monotonic variation of the elemental surface composition, modification of the valence band, progressive hydroxylation of the surface and increasing dispersion of vanadium oxide species. Increasing pH was also accompanied by an increase in the abundance of V 4? species, specific surface area and reducibility. Calcination in air at 500°C gave rise to surface segregation of vanadium, changes in the valence band and partial dehydroxylation. The structural transformations in vanadium oxide species and aluminium hydroxide support and their interaction were accompanied by an increasing abundance of V-O-Al bonds. The net result of the restructuring was a decrease in the specific surface area and reducibility of the calcined catalysts. The enhancement of the catalytic activity in propane oxidative dehydrogenation demonstrated by V-Al-O samples with increasing precipitation pH and after calcination was in good correlation with a growing population of the V 4? states and increasing nucleophilicity of oxygen sites.

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“…A final remark should be made about the formation of mixed metal oxides upon heating of supported vanadium oxide catalysts. It has been shown that MgV 2 O 7 and ZrV 2 O 7 can be formed when V/MgO and V/ZrO 2 catalysts, respectively are calcined in air [190][191][192][193].…”

Section: Catalyst Calcinationmentioning

confidence: 99%

“…V 5+ , V 4+ and V 3+ ) and coordination environments (i.e. VO 4 , VO 5 and VO 6 ) [193]. Many authors have determined the average oxidation state of supported vanadium oxides after reduction with temperature programmed reduction (TPR) techniques, mainly H 2 -TPR techniques [194,195].…”

Section: Catalyst Activationmentioning

confidence: 99%

Chemistry, Spectroscopy and the Role of Supported Vanadium Oxides in Heterogeneous Catalysis

Weckhuysen

Keller

2003

ChemInform

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Supported vanadium oxide catalysts are active in a wide range of applications. In this review, an overview is given of the current knowledge available about vanadium oxide-based catalysts. The review starts with the importance of vanadium in heterogeneous catalysis, a discussion of the molecular structure of vanadium in water and in the solid state and an overview of the spectroscopic techniques enabling to study the chemistry of supported vanadium oxides. In the second part, it will be shown that advanced spectroscopic tools can be used to obtain detailed information about the coordination environment and oxidation state of vanadium oxides during each stage of the life-span of a heterogeneous catalyst. Three topics will be discussed: (1) the molecular structure of supported vanadium oxide catalysts under hydrated, dehydrated and reduced conditions, including the parameters, which influence the molecular structures formed at the surface of the support oxide; (2) elucidation of the active surface vanadium oxide during the oxidation of methanol to formaldehyde, the reaction mechanism and the vanadium oxide-support effect; and (3) deactivation of fluid catalytic cracking (FCC) catalysts by migration of vanadium oxides and the development of a method preventing the structural breakdown of zeolites by trapping the mobile vanadium oxides in an aluminum oxide coating.

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Alumina-Supported Vanadium Oxide in the Dehydrogenation of Butanes

Cited by 109 publications

References 24 publications

The role of carbon species in heterogeneous catalytic processes: an in situ soft x-ray photoelectron spectroscopy study

The role of carbon species in heterogeneous catalytic processes: an in situ soft x-ray photoelectron spectroscopy study

XPS–SIMS Surface Characterization of Aluminovanadate Oxide Catalyst Precursors Co-Precipitated at Different pH: Effect of Calcination

Chemistry, Spectroscopy and the Role of Supported Vanadium Oxides in Heterogeneous Catalysis

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