V–Ti and V–Al silicate molecular sieves of MFI topology: synthesis and characteristics

Kornatowski, J.; Sychev, MV; Kuzenkov, Serioža; Strnadová, K; Pilz, W.; Kassner, Dethard; Pieper, G.; Baur, W. H.

doi:10.1039/ft9959102217

Cited by 30 publications

(22 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies done on crystalline materials highlighted that the frequency of the oxygen-vanadium chargetransfer excitation band provides information regarding the number of oxygen ligands surrounding vanadium. Indeed, by increasing oxygen coordination around V 5+ species from 4 to 6, the absorption bands redshift from ∼275 and ∼340 to ∼400 to ∼470 cm −1 , as observed for NaVO 3 ( [4] V 5+ ), VPO 4 ( [5] V 5+ ) and V 2 O 5 ( [6] V 5+ ), respectively (Schraml-Marth et al, 1991;Kornatowski et al, 1995) and references therein.…”

Section: Photoluminescencementioning

confidence: 61%

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Cicconi¹,

Lu²,

Uesbeck

et al. 2020

Front. Mater.

View full text Add to dashboard Cite

V 2 O 5 was introduced up to 9 wt.% in a peralkaline alkaline earth aluminosilicate glass and up to 4.8 wt.% in two sodo aluminosilicate glasses, respectively, a peralkaline and a peraluminous one. This introduction had a strong effect on thermal properties, and in particular, on glass transition and crystallization temperatures of the peraluminous glass, which dropped by 89 K, while a moderate drop of ∼20 K was observed for the two other glasses. Still, the glass stability and the glass-forming ability stayed almost unmodified. The elastic properties measured by Brillouin spectroscopy show a decrease with added Vanadium for the depolymerized alkali earth aluminosilicate and the peraluminous sodo aluminosilicate. In contrast, the elastic properties remained unchanged for the peralkaline composition. Using optical absorption, the proportion of V 5+ , which is largely dominant, was found to follow the trend predicted using optical basicity considerations. A large photoluminescence emission, centered at ∼560 nm, was found for all glasses, upon excitation in the UV edge at both ∼280 and ∼350 nm. The emission band positions were relatively insensitive to the glass composition, whereas their intensities show variations of one order of magnitude between the sodium peralkaline composition and the calcium depolymerized glass. A too-high concentration of V 2 O 5 shows a quenching effect on the emission. Polarized and cross-polarized Raman spectroscopy allowed us to identify the different environments around the V 5+ O 4 tetrahedra. The highly polarizable V 5+ O 4 tetrahedra associated with two non-bridging oxygens, vibrating at 860 cm −1 , is proposed to be responsible for the more efficient charge transfer. At the opposite end, the formation of VO 4 -AlO 4 units is proposed to quench luminescence properties. Furthermore, we observed that, upon thermal treatment, the optical properties of the glasses are significantly modified without observable structural modifications or evolution of the elastic properties.

show abstract

Section: Photoluminescencementioning

confidence: 61%

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Cicconi¹,

Lu²,

Uesbeck

et al. 2020

Front. Mater.

View full text Add to dashboard Cite

show abstract

“…EPR,14h17 51V NMR10,17h19 and UVÈVIS spectroscopies. 16,17,20 These can all contribute to the characterization of vanadium species, but all have their drawbacks. In particular, EPR can characterize vanadium only in the oxidation state ] 4, which is, on the other hand, not visible in 51V NMR.…”

mentioning

confidence: 99%

Investigation of zeolites by photoelectron and ion scattering spectroscopy Part IV XPS studies of vanadium-modified zeolites

Wark¹,

Koch²,

Brückner³

et al. 1998

Faraday Trans.

View full text Add to dashboard Cite

“…The other cations, e.g., the TM cations, responsible for the redox properties of the zeolitic systems, can also be introduced into the zeolite framework, and this property is most often accompanied by the presence of acidic centres, thus forming the bi-functional catalysts [11]. The TM ions can occupy both the framework positions (via the isomorphic substitution), see, e.g., [12][13][14][15], or the extraframework positions (ion exchangeable sites) [16][17][18]. Due to easier accessibility, the latter case is most commonly found in catalysis.…”

Section: Zeolite Structurementioning

confidence: 99%

Structural Studies of Aluminated form of Zeolites—EXAFS and XRD Experiment, STEM Micrography, and DFT Modelling

et al. 2021

View full text Add to dashboard Cite

In this article, the results of computational structural studies on Al-containing zeolites, via periodic DFT + D modelling and FDM (Finite Difference Method) to solve the Schrödinger equation (FDMNES) for XAS simulations, corroborated by EXAFS (Extended X-ray Absorption Fine Structure) spectroscopy and PXRD (powder X-ray diffractometry), are presented. The applicability of Radial Distribution Function (RDF) to screen out the postulated zeolite structure is also discussed. The structural conclusions are further verified by HR-TEM imaging.

show abstract

V–Ti and V–Al silicate molecular sieves of MFI topology: synthesis and characteristics

Cited by 30 publications

References 28 publications

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Investigation of zeolites by photoelectron and ion scattering spectroscopy Part IV XPS studies of vanadium-modified zeolites

Structural Studies of Aluminated form of Zeolites—EXAFS and XRD Experiment, STEM Micrography, and DFT Modelling

Contact Info

Product

Resources

About