K/Mo Catalysts Supported over Sol–Gel Silica–Titania Mixed Oxides in the Oxidative Dehydrogenation of Propane

Watson, Rick B.; Ozkan, Umit S.

doi:10.1006/jcat.1999.2781

Cited by 112 publications

(66 citation statements)

References 45 publications

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“…Mixed SiO 2 -TiO 2 materials have attracted many researchers, because it has been shown that mixed SiO 2 -TiO 2 materials can provide certain advantages over single oxides. Benefits such as stronger metal-support interactions, higher acidity compared to single oxides, better resistance to sintering, and resistance against sulfur poisoning have been observed in earlier studies [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 67%

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Catalytic Activity Studies of Vanadia/Silica–Titania Catalysts in SVOC Partial Oxidation to Formaldehyde: Focus on the Catalyst Composition

et al. 2018

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Abstract:In this work, silica-titania supported catalysts were prepared by a sol-gel method with various compositions. Vanadia was impregnated on SiO 2 -TiO 2 with different loadings, and materials were investigated in the partial oxidation of methanol and methyl mercaptan to formaldehyde. The materials were characterized by using N 2 physisorption, X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS), Scanning transmission electron microscope (STEM), NH 3 -TPD, and Raman techniques. The activity results show the high importance of an optimized SiO 2 -TiO 2 ratio to reach a high reactant conversion and formaldehyde yield. The characteristics of mixed oxides ensure a better dispersion of the active phase on the support and in this way increase the activity of the catalysts. The addition of vanadium pentoxide on the support lowered the optimal temperature of the reaction significantly. Increasing the vanadia loading from 1.5% to 2.5% did not result in higher formaldehyde concentration. Over the 1.5%V 2 O 5 /SiO 2 + 30%TiO 2 catalyst, the optimal selectivity was reached at 415 • C when the maximum formaldehyde concentration was~1000 ppm.

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Section: Introductionmentioning

confidence: 67%

“…The sol-gel preparation procedure, not only being a rather easy way to prepare catalyst materials, provides advantages over the SiO 2 -TiO 2 preparation process [6,8,9]. The sol-gel preparation steps include sol (colloid suspension) preparation, alkoxysilane hydrolysis, and condensation of silica and titania precursors.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Activity Studies of Vanadia/Silica–Titania Catalysts in SVOC Partial Oxidation to Formaldehyde: Focus on the Catalyst Composition

et al. 2018

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“…At present, the maximum propene yield by ODP amounts to about 30 %. This yield was reached for K-Mocatalysts on SiO 2 /TiO 2 -supports [4]. However, these experiments were performed with a very diluted feed, which leads to technical unrealistic space-time yields.…”

Section: Introductionmentioning

confidence: 95%

Hierarchical Nano‐structuring of Metal Oxide Catalysts – Part 1: Influence of Nano‐structuring on the Activity of the Catalysts

Stelzer¹,

Caro

Habel

et al. 2004

Chem Eng & Technol

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The oxidative dehydrogenation of short‐chain alkanes is a suitable model reaction to show correlations between the catalyst structure and the catalytic performance. For all investigated catalysts propane conversion increases with increasing amounts of the catalyticly active components V2O5, MoO3, or TiO2. It is proposed that the catalytic activity is related to the number and size of the contact zones between support and active component.

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“…9 Abello et al 10 showed a significant increase in selectivity on Mo/MgO-gAl 2 O 3 with the addition of potassium.…”

Section: Introductionmentioning

confidence: 99%

The influence of the amount and impregnation sequence of potassium on the catalytic performance of VOx/Al2O3 for the non-oxidative dehydrogenation of n-butane

Volpe

García

2012

J. Braz. Chem. Soc.

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A dehidrogenação não-oxidativa de n-butano foi estudado usando catalisadores de vanádio suportados em alumina e potássio como promotor (a 873 K e pressão atmosfera), a fim de se explorar a influência da quantidade e da ordem de agregação do metal alcalino na atividade catalítica e seletividade de olefinas. A atividade e seletividade da dehidrogenação não-oxidativa diminuíram com o aumento da razão molar K/V. O melhor desempenho catalítico foi obtido com 1 wt.% de potássio e quando o promotor foi agregado pela primeira vez nos catalisadores de vanádio suportados em alumina. A ordem de agregação do promotor tem efeitos na atividade catalítica. Dados de TPR (redução à temperatura programada) indicam que menos espécies de vanádio são acessíveis à redução quando baixa quantidade (1 wt.%) de promotor metal alcalino foi impregnada no catalisador antes do vanádio. Após tratamento de regeneração, estes catalisadores não recuperam a plena atividade. Tendo em conta os resultados de TPR, essa desativação do catalisador pode estar relacionada com a transformação estrutural irreversível de espécies de óxido de vanádio superficiais pelo potássio.The non-oxidative dehydrogenation of n-butane was studied over potassium-promoted supported vanadium alumina catalysts (at 823 K under atmosphere pressure) to explore the influence of the amount and the order of potassium aggregation on the catalytic activity and selectivity towards olefins. The non-oxidative dehydrogenation activity and selectivity decreased with increasing K/V molar ratio. The best catalytic performance was obtained with 1 wt.% of potassium loading and when the promoter was first aggregated in the supported vanadium alumina catalysts. The order of promoter aggregation has effects in the catalytic activity. TPR (temperature programmed reduction) data indicate that less vanadium species are accessible to the reduction when low amount (1 wt.%) of alkali metal promoter was first introduced in these samples. After regeneration treatment, these promoted catalysts did not recover the full activity. Taking in account TPR results, this catalyst deactivation may be related to the irreversible structural transformation of surface vanadium oxide species by potassium.

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K/Mo Catalysts Supported over Sol–Gel Silica–Titania Mixed Oxides in the Oxidative Dehydrogenation of Propane

Cited by 112 publications

References 45 publications

Catalytic Activity Studies of Vanadia/Silica–Titania Catalysts in SVOC Partial Oxidation to Formaldehyde: Focus on the Catalyst Composition

Catalytic Activity Studies of Vanadia/Silica–Titania Catalysts in SVOC Partial Oxidation to Formaldehyde: Focus on the Catalyst Composition

Hierarchical Nano‐structuring of Metal Oxide Catalysts – Part 1: Influence of Nano‐structuring on the Activity of the Catalysts

The influence of the amount and impregnation sequence of potassium on the catalytic performance of VOx/Al2O3 for the non-oxidative dehydrogenation of n-butane

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