V2O5–SiO2 systems prepared by flame pyrolysis as catalysts for the oxidative dehydrogenation of propane

Rossetti, Ilenia; Fabbrini, Laura; Ballarini, Nicola; Oliva, Cesare; Cavani, Fabrizio; Cericola, Antonio; Bonelli, Barbara; Piumetti, Marco; Garrone, Edoardo; Dyrbeck, H.

doi:10.1016/j.jcat.2008.02.028

Cited by 58 publications

(86 citation statements)

References 52 publications

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“…More detailed data have been reported elsewhere [20][21]. For both the preparation methods the conversion was lower, but the selectivity was higher with SiO2-than with Al2O3-supported catalysts.…”

Section: -Resultsmentioning

confidence: 68%

“…The FP preparation of V-based catalysts supported on silica or alumina has been recently described by our group [20,21] as a mean to obtain nanosized catalysts with /g for SiO2, depending on V loading) and ultimately related to the preparation protocol. Lower surface area was indeed achieved during the preparation of the alumina supported samples due to the need of dissolving the aluminum precursor in alcohols, which usually lead to worse powder properties [17,18,21].…”

Section: Discussionmentioning

confidence: 99%

“…The feeding solutions have been prepared as described in [20,21], using Al(NO3)3*9H2O, tetra-ethyl-orthosilicate (TEOS) and V oxi-acetyl-acetonate as precursors.…”

Section: -Sample Preparationmentioning

confidence: 99%

“…We applied such a synthesis procedure to the preparation of silica-and alumina-supported V samples, which were tested as catalysts for the ODH of propane [20,21]. On the basis of such results, it can be hypothesised that, at least for FP-prepared silica-supported samples, V was more easily inserted into the support matrix, leading to a higher dispersion of the active sites, at difference with samples of similar composition prepared by different…”

Section: -Introductionmentioning

confidence: 99%

“…An extensive description of the catalytic performance and physical-chemical properties of these samples has been reported elsewhere [20,21]. In the present investigation we concentrated on their characterisation by Electron Paramagnetic Resonance (EPR), a powerful tool to address the local structure of V 4+ sites.…”

Section: -Introductionmentioning

confidence: 99%

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EPR enlightening some aspects of propane ODH over VOx–SiO2 and VOx–Al2O3

Oliva

Cappelli

Rossetti

et al. 2009

Chemical Engineering Journal

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In the oxidative dehydrogenation (ODH) of propane to propylene VOx-based catalysts prepared by flame pyrolysis (FP) showed more selective than those prepared by impregnation. Furthermore, samples prepared by the same method were less active, but more selective when VOx was supported on SiO2 than on Al2O3. In order to assess V local structure, V 4+ ions showed useful labels to characterise these catalysts by EPR spectroscopy. Indeed, the spectrum of a (10 wt%V2O5) FP-prepared VOx/SiO2 catalyst was typical of isolated, tetragonally distorted, paramagnetic complexes of V 4+ forming a monolayer on the sample surface with a strong out-of-plane V 4+ -O bond. In a sample with identical composition, but prepared by impregnation, this bond showed a bit weaker.Furthermore, ferromagnetic domains of clustered V ions formed in the latter sample, hindering at least in part the accessibility to the catalytically active V-based centres. This gives evidence of the higher dispersion of V in the sample bulk provided by the FP preparation method with respect to conventional ones. A by far weaker V 4+ -O bond was revealed by the EPR spectrum of a (10%V2O5) VOx/Al2O3 sample, accounting for its higher oxygen availability, leading to higher activity, but lower selectivity. However, the same catalyst, when prepared by impregnation, showed a ferromagnetic resonance pattern so intense that no EPR spectrum was detectable at all and no information on the V 4+ -O bond strength was available in that case.Such semi-quantitative index of the V-O bond strength can be used as an index of oxygen availability, as a tool to assess catalytic activity and selectivity to the desired olefin.

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Section: -Resultsmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

“…The feeding solutions have been prepared as described in [20,21], using Al(NO3)3*9H2O, tetra-ethyl-orthosilicate (TEOS) and V oxi-acetyl-acetonate as precursors.…”

Section: -Sample Preparationmentioning

confidence: 99%

Section: -Introductionmentioning

confidence: 99%

Section: -Introductionmentioning

confidence: 99%

See 3 more Smart Citations

EPR enlightening some aspects of propane ODH over VOx–SiO2 and VOx–Al2O3

Oliva

Cappelli

Rossetti

et al. 2009

Chemical Engineering Journal

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Flame Aerosol Synthesis of Metal Oxide Catalysts with Unprecedented Structural and Catalytic Properties

2011

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In the past two decades flame aerosol synthesis of novel materials has experienced significant growth in both industry and academia. Recent research is focused on the development of new materials in the nanosized range to be used in various applications, such as catalysts, gas sensors, pigments, and batteries. Several studies indicate that this scalable synthesis method can result in novel and metastable phases of mixed metal oxides of high purity, which may not be easy accessible by conventional wet‐ or solid‐state processes. Especially for catalytic applications this synthesis method is emerging as an attractive fast and single‐step production route for high surface area materials, often with unprecedented structural and catalytic properties. The large variety of possible organometallic precursors especially for the liquid‐fed aerosol flame synthesis makes this technique very versatile for catalyst synthesis. Using the example of the widely used vanadia‐based mixed oxide catalysts, we analyze the structural and catalytic properties of flame‐derived catalysts and compare them to corresponding catalysts prepared by classical wet‐chemistry methods. The often unique structural properties along with their control at proper synthesis conditions and their influence on catalyst performance in selected reactions are discussed. Subsequently, we give an overview of other recent flame‐made mixed metal oxide based catalysts and make an attempt to assess the potential and limitations of flame synthesis for the preparation of catalytic mixed metal oxide materials, and finally we identify future challenges in research.

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Nickel Catalysts Supported Over TiO₂, SiO₂ and ZrO₂ for the Steam Reforming of Glycerol

et al. 2012

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Ni‐based catalysts supported on TiO2, ZrO2 and SiO2 (in the form of mesoporous Santa Barbara Amorphous 15 (SBA‐15) and amorphous dense nanoparticles), were employed in the steam reforming of glycerol. Each sample was prepared by liquid phase synthesis of the support followed by impregnation with the active phase and calcination at 800 °C or by direct synthesis through flame pyrolysis. Many techniques have been used to assess the physical chemical properties of both the fresh and spent catalysts, such as atomic absorption, N2 adsorption/desorption, XRD, SEM, TEM, temperature‐programmed reduction (TPR), X‐ray photoelectron spectroscopy (XPS), Micro‐Raman and FTIR spectroscopy. The samples showed different textural, structural and morphological properties, as well as different reducibility and thermal resistance depending on the preparation method and support. Some of these properties were tightly bound to catalyst performance, in terms of H2 productivity and stability towards coking and sintering. A key parameter was the metal–support interaction, which strongly depended on the preparation procedure. In particular, the stronger the interaction, the more stable the metallic Ni clusters, which in turn lead to a higher catalytic activity and stability. Surface acidity was also taken into account, in which the nature of the acid sites was differentiated (silanols, titanols or Lewis acid sites). The characterisation of the spent catalysts also allowed us to interpret the deactivation process. The formation of multi‐walled nanotubes was observed for every sample, though it was only in some cases that this led to severe deactivation.

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V2O5–SiO2 systems prepared by flame pyrolysis as catalysts for the oxidative dehydrogenation of propane

Cited by 58 publications

References 52 publications

EPR enlightening some aspects of propane ODH over VOx–SiO2 and VOx–Al2O3

EPR enlightening some aspects of propane ODH over VOx–SiO2 and VOx–Al2O3

Flame Aerosol Synthesis of Metal Oxide Catalysts with Unprecedented Structural and Catalytic Properties

Nickel Catalysts Supported Over TiO₂, SiO₂ and ZrO₂ for the Steam Reforming of Glycerol

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V2O5–SiO2 systems prepared by flame pyrolysis as catalysts for the oxidative dehydrogenation of propane

Cited by 58 publications

References 52 publications

EPR enlightening some aspects of propane ODH over VOx–SiO2 and VOx–Al2O3

EPR enlightening some aspects of propane ODH over VOx–SiO2 and VOx–Al2O3

Flame Aerosol Synthesis of Metal Oxide Catalysts with Unprecedented Structural and Catalytic Properties

Nickel Catalysts Supported Over TiO2, SiO2 and ZrO2 for the Steam Reforming of Glycerol

Contact Info

Product

Resources

About

Nickel Catalysts Supported Over TiO₂, SiO₂ and ZrO₂ for the Steam Reforming of Glycerol