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Lopez, Hector; Martı́nez, Agustı́n

doi:10.1023/a:1020649313699

Cited by 42 publications

(26 citation statements)

References 20 publications

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“…Furthermore, it opens the possibility to study catalysis on well-defined, spatially separated transition metal centers. Despite its great potential use for catalytic applications, there have been only few reports on the preparation and application of SBA-15 supported vanadium oxide catalysts [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

The mechanism for the controlled synthesis of highly dispersed vanadia supported on silica SBA-15

Heß

Wild

Schlögl

2006

Microporous and Mesoporous Materials

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The mechanism for the controlled synthesis of highly dispersed vanadia supported on mesoporous silica SBA-15 (VO x /SBA-15) is elucidated using X-ray photoelectron spectroscopy (XPS), Raman and diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS). The synthesis consists of functionalization of SBA-15 using 3-aminopropyltrimethoxysilane (APTMS) followed by HCl treatment, anion exchange of decavanadate (V 10 O 28 6-) and calcination to yield the final material. Spectroscopic analysis yields that APTMS is grafted onto the surface via hydroxyl groups. Under ambient conditions, protonated APTMS on SBA-15 is largely hydrolyzed and present in its bidentate and tridentate form. Detailed XPS analysis reveals a strong influence of surface water on the resulting structure of APTMS on SBA-15. Under dry conditions, the protonated APTMS molecules on SBA-15 adopt the monodentate and bidentate form. During the anion exchange reaction, decavanadate is incorporated intactly into the pores, without any changes in the structure of the organic framework. In the calcination step, decavanadate is decomposed and vanadia is anchored onto the surface of SBA-15 via silanol groups resulting in highly dispersed surface vanadia species, while the organic resiues are fully removed from the pores of the silica matrix. d

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Section: Introductionmentioning

confidence: 99%

The mechanism for the controlled synthesis of highly dispersed vanadia supported on silica SBA-15

Heß

Wild

Schlögl

2006

Microporous and Mesoporous Materials

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“…Only recently, we have demonstrated the excellent performance of this catalyst system in methanol oxidation to formaldehyde and in propane oxidation to acrylic acid. 36,37 Although of great potential for catalytic applications, there have been only few reports on the preparation and reactivity behavior of SBA-15-supported vanadia catalysts.…”

Section: Introductionmentioning

confidence: 99%

Redox Properties of Vanadium Ions in SBA-15-Supported Vanadium Oxide: An FTIR Spectroscopic Study

2006

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“…thinner-walled MCM-41 [3]. Although of great potential use for catalytic applications, there have been only few reports on the preparation of SBA-15 supported catalysts by impregnation methods [4,5]. However, controlled synthesis of catalytic materials with uniform active sites is still a challenge.…”

Section: Introductionmentioning

confidence: 99%

“…Silica-supported vanadia catalysts are very selective towards formaldehyde, but exhibit a rather low activity in comparison to a series of vanadia catalysts supported on other oxides, such as titania [9,12]. Only recently, the reactivity behavior of SBA-15 supported vanadia was studied for the photo-induced oxidation of methane to formaldehyde [4] and oxidative dehydrogenation (ODH) of propane [5].…”

Section: Introductionmentioning

confidence: 99%

Characterization of the synthesis and reactivity behavior of nanostructured vanadia model catalysts using XPS and vibrational spectroscopy

Heß

2006

Surface Science

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Nanostructured vanadia model catalysts, i.e. highly dispersed vanadium oxide supported on mesoporous silica SBA-15 (VO x /SBA-15), were prepared. The mechanism for the synthesis of VO x /SBA-15 was elucidated by detailed characterization of the individual synthesis steps using XPS and vibrational spectrocopy. The resulting surface vanadium oxide species (0 -2.3 V/nm 2 ), grafted on the inner pores of the SBA-15 silica matrix, consists of tetrahedrally coordinated vanadia as inferred from UV-VIS-and Raman spectroscopy. The prepared vanadia model catalysts were tested in the partial oxidation of methanol to formaldehyde yielding high formaldehyde selectivities of 94% at 350ºC. XPS and Raman analysis of the catalyst after reaction reveal the presence of methoxy as well as a significant amount of carbonaceous species on the surface. Our results demonstrate that a detailed understanding of partial oxidation reactions requires the combination of complementary spectroscopic techniques ultimately within one experimental set-up.

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Cited by 42 publications

References 20 publications

The mechanism for the controlled synthesis of highly dispersed vanadia supported on silica SBA-15

The mechanism for the controlled synthesis of highly dispersed vanadia supported on silica SBA-15

Redox Properties of Vanadium Ions in SBA-15-Supported Vanadium Oxide: An FTIR Spectroscopic Study

Characterization of the synthesis and reactivity behavior of nanostructured vanadia model catalysts using XPS and vibrational spectroscopy

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