Oxidative dehydrogenation of propane over low-loaded vanadia catalysts: Impact of the support material on kinetics and selectivity

Dinse, Arne; Frank, Benjamin; Heß, Christian; Habel, Daniela; Schomäcker, Reinhard

doi:10.1016/j.molcata.2008.04.007

Cited by 112 publications

(125 citation statements)

References 53 publications

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“…The differences in the selectivity-conversion behavior at equal reaction conditions have been discussed in detail before. 11 The results of this study show that there is a strong influence of the support material on the catalyst activity and product selectivity. The selectivity at a given propane conversion decreases in the order V-Al 2 O 3 > V-TiO 2 > V-SiO 2 .…”

Section: Resultsmentioning

confidence: 71%

“…This is suggested by Raman spectra of these catalysts presented in a previous publication. 11 In order to derive a correlation between persistent reduced states and catalytic performance a quantitative study invoking comparable reaction conditions will be performed in the future.…”

Section: Discussionmentioning

confidence: 99%

“…Kinetic studies, 11,12 however, indicate that direct oxidation of propane to carbon oxides occurs only to a small extent.…”

Section: Introductionmentioning

confidence: 99%

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Potential of High-Frequency EPR for Investigation of Supported Vanadium Oxide Catalysts

et al. 2008

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Supported vanadium oxide catalysts were studied by high-frequency EPR for determination of the paramagnetic vanadium oxidation states vanadium(IV) and vanadium(III). TiO 2 -, γ-Al 2 O 3 -, and SiO 2 (SBA-15)-supported catalysts were investigated before and after being used for the oxidative dehydrogenation of propane. While the SBA-15-supported catalyst exhibits only one distinct position of vanadium species with the oxidation state IV, Al 2 O 3 reveals a distribution of vanadium(IV) sites. For this support material formation of oxoradicals has been observed, indicating its capability for trapping electrons during the catalytic cycle. The TiO 2 -supported material apparently does not stabilize vanadium(IV), which can be attributed to either a high mobility of existing oxygen vacancies or the competitive capability of titanium(IV) surface states to trap electrons. Titanium in its oxidation state of vanadium(III) and surface-trapped O 2 (-) species were identified as potential electron sinks in the case of the TiO 2 -supported catalyst. The increase in catalytic activity in the order of SBA-15 < Al 2 O 3 < TiO 2 therefore could be caused by different reduction mechanisms depending on the chosen support material. No vanadium in its oxidation state III was detected in any of the samples, which indicates that such species are either short lived or not existent during the oxidative dehydrogenation of propane.

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Section: Resultsmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 99%

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Potential of High-Frequency EPR for Investigation of Supported Vanadium Oxide Catalysts

et al. 2008

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“…Spinel lanthanum chromites (LaCrO 3 ) is one of the perovskite materials that has been extensively studied due to its applicability as interconnector for solid oxide fuel cell (SOFC's), high chemical stability, good electrical properties at high temperature 24 -26 , and catalytic activity for total oxidation 27 , partial oxidation 28 , oxidative dehydrogenation 29 , and photocatalyst 30 . Perovskite compounds have been prepared using various methods such as hydrothermal 19,31,32 , precipitation 16,33 , co-precipitation 34,35 , autocombustion 36,37 , and sol -gel 38 -40 .…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Nano-Size LaCrO3 Prepared Through Sol-Gel Route Using Pectin as Emulsifying Agent

Situmeang¹,

Supryanto²,

Kahar³

et al. 2017

Orient. J. Chem

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In this study, nano-size LaCrO 3 was prepared through sol-gel route using pectin as emulsifying agent, followed by freeze -drying to obtain solid sample. The sample was prepared by mixing the solution of La(NO 3 ) 3 .6 H 2 O and Cr(NO 3 ) 3 .9 H 2 O with pectin solution under magnetic stirring. The sample was frozen and subsequently subjected to freeze -drying and calcination treatment at temperatures of 600, 700 and 800 ºC for 6 h. The calcined samples were characterized with several techniques. The phase composition was evaluated using the X-ray diffraction (XRD) technique, followed by crystallite size calculation using Scherrer Methods. The functionality of sample was identified using Fourier transform infrared (FTIR) spectroscopy, surface structure in three dimensional images was analyzed using Transmission electron microscopy (TEM), and particle size distribution was determined by Particles Size Distribution (PSA). The results of XRD characterization indicated that materials consist of various crystalline phases, with LaCrO 3 as a major phase. FTIR Analysis revealed the existence of both Lewis and BrØnsted -Lowry acid sites, with Lewis acid as the prominent sites, represented by the absorption band located at around 1636 cm -1 . The samples were found to display relatively homogeneous surface morphology, having the crystallite size in the range of 24 to 25 nm according to Scherrer equation. The PSA analyses revealed increased relative percentages of nano-size portion in the sample from 22 to 89% as temperatures increased from 600 to 800 ºC, with the particle size in the range of 30 to 35 nm as seen by the TEM .

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“…Among several differently supported VO x catalysts prepared under comparable conditions the alumina supported sample showed the best catalytic performance in ODP with respect to propene selectivity [39]. The VO x /γ-Al 2 O 3 catalyst VA-200, introduced in a recent article [19], was thereby chosen for this study, however, a similar investigation is projected for low loaded SiO 2 (SBA-15) supported vanadium oxide samples [40].…”

Section: Introductionmentioning

confidence: 99%

Reoxidation dynamics of highly dispersed VOx species supported on γ-alumina

Frank¹,

Fortrie²,

Heß³

et al. 2009

Applied Catalysis A: General

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The VO x /γ-Al 2 O 3 catalyst VA-200, which was introduced in a previous article, is further characterized by XPS and visible Raman spectroscopy. The reoxidation of highly dispersed VO x species with gas phase oxygen is investigated in detail and is described by an empirical kinetic model. It is observed that the reoxidation of reduced VO x /γ-Al 2 O 3 catalyst is strongly affected by the presence of water. The proposed kinetic model includes a distinct coverage of VO x species with water or hydroxyl groups in the investigated temperature range of 479-712 K. Hydrated surface species are oxidized under release of water. Best fits of the experimental data can be achieved with first order rate laws with respect to oxygen concentration. Experiments are performed in an ideally mixed Berty-type reactor using oxygen step-marking over the reduced catalyst. The evolution of oxygen concentration using the kinetic model is in agreement with the experimentally observed behavior. The signal of water released during the reaction can be modeled only qualitatively, which (presumably) stems from its sorption behavior on the acidic alumina support. The oxidation of VO x species furthermore depends on the reaction temperature. The oxidation of V +III to V +V cannot be completely achieved at temperatures below 673 K. However, the activation energy of this reaction is low, as suggested by the absence of strong variations of the response shapes with respect to temperature.

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Oxidative dehydrogenation of propane over low-loaded vanadia catalysts: Impact of the support material on kinetics and selectivity

Cited by 112 publications

References 53 publications

Potential of High-Frequency EPR for Investigation of Supported Vanadium Oxide Catalysts

Potential of High-Frequency EPR for Investigation of Supported Vanadium Oxide Catalysts

Characteristics of Nano-Size LaCrO3 Prepared Through Sol-Gel Route Using Pectin as Emulsifying Agent

Reoxidation dynamics of highly dispersed VOx species supported on γ-alumina

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