Conversion of 1-butene over WO3-TiO2 Catalysts

Patrono, P.; Ginestra, A. La; Ramis, Gianguido; Busca, Guido

doi:10.1016/0926-860x(94)85159-x

Cited by 60 publications

(35 citation statements)

References 22 publications

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“…This trend is accompanied by the formation of Brønsted acid sites. The detection of Brønsted acid sites in WO x /TiO 2 is in agreement with previous infrared studies of ammonia [16][17][18][19][20], pyridine [18] and CO adsorption [5,16].…”

Section: Wo X /Tiosupporting

confidence: 78%

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Acidity of titania-supported tungsten or niobium oxide catalystsCorrelation with catalytic activity

Onfroy

Clet

Bukallah

et al. 2006

Applied Catalysis A: General

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The acidity of catalytic systems based on tungsten oxide or niobium oxide supported on titania was compared. Two series with metal contents up to 3.6 atom nm À2 were prepared by incipient wetness impregnation of the titania support with ammonium metatungstate or niobium oxalate solutions. Characterization of both systems by X-ray diffraction and Raman spectroscopy studies did not show evidence of bulk metal oxide formation. The acidity was monitored by adsorption of 2,6-dimethylpyridine (2,6-lutidine) followed by infrared spectroscopy. The catalytic activity was tested for the reaction of isopropanol dehydration.At a reaction temperature of 403 K, WO x /TiO 2 catalysts were inactive for a surface density of W 1.2 W atom nm À2 . Above this loading, the activity increased progressively with increasing W content. Similar evolution was observed for the abundance of relatively strong Brønsted acid sites (i.e. able to retain lutidine at 573 K). In contrast, NbO x /TiO 2 catalysts were essentially inactive at this reaction temperature and a higher reaction temperature (473 K) was required to reach a comparable catalytic activity. No threshold of Nb loading for the development of catalytic activity was observed. Similar behavior was evidenced for the abundance of medium strength Brønsted acid sites (able to retain lutidine at 523 K). For both systems, a direct correlation between the catalytic activity and the abundance of Brønsted acid sites was observed. #

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Section: Wo X /Tiosupporting

confidence: 78%

“…Towards this objective, the surface structure and catalytic properties of titania-supported W and Nb systems will be examined. These systems have also been shown to exhibit acidic properties [5,10,11,[16][17][18][19][20][21]. Characterization of both systems will be conducted by X-ray diffraction and Raman spectroscopy studies.…”

Section: Introductionmentioning

confidence: 99%

Acidity of titania-supported tungsten or niobium oxide catalystsCorrelation with catalytic activity

Onfroy

Clet

Bukallah

et al. 2006

Applied Catalysis A: General

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“…In contrast, for the catalytic combustion of toluene to CO 2 , oxygen vacancies resulting in nonstoichiometric tungsten oxide were found to be critical to the observed activity (42). Moreover, the isomerization of 1-butene to isobutene was observed to be most selective over oxygen-rich tungsten oxides containing WO 4 2Ϫ surface sites (43,44). These bulk-phase findings suggest that the stoichiometry of tungsten oxide particles directly influences both their activity and selectivity for catalytic reactions.…”

mentioning

confidence: 53%

“…Bulk-phase studies have shown tungsten oxides to be catalytically active for the selective oxidation of sulfides to sulfoxides (41), the combustion of toluene (42), the skeletal isomerization of 1-butene (43,44), and the decomposition of simple alcohols (45). Monoclinic, stoichiometric WO 3 particles in the size range of 2-5 nm have been found to be the active species for the selective oxidation of sulfides to sulfoxides (41).…”

mentioning

confidence: 99%

Cluster reactivity experiments: Employing mass spectrometry to investigate the molecular level details of catalytic oxidation reactions

Johnson

Tyo

Castleman

2008

Proc. Natl. Acad. Sci. U.S.A.

117

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Mass spectrometry is the most widely used tool in the study of the properties and reactivity of clusters in the gas phase. In this article, we demonstrate its use in investigating the molecular-level details of oxidation reactions occurring on the surfaces of heterogeneous catalysts via cluster reactivity experiments. Guided ion beam mass spectrometry (GIB-MS) employing a quadrupole-octopolequadrupole (Q-O-Q) configuration enables mass-selected cluster ions to be reacted with various chemicals, providing insight into the effect of size, stoichiometry, and ionic charge state on the reactivity of catalyst materials. For positively charged tungsten oxide clusters, it is shown that species having the same stoichiometry as the bulk, WO 3 ؉ , W2O 6 ؉ , and W3O 9 ؉ , exhibit enhanced activity and selectivity for the transfer of a single oxygen atom to propylene (C 3H6), suggesting the formation of propylene oxide (C 3H6O), an important monomer used, for example, in the industrial production of plastics. Furthermore, the same stoichiometric clusters are demonstrated to be active for the oxidation of CO to CO 2, a reaction of significance to environmental pollution abatement. The findings reported herein suggest that the enhanced oxidation reactivity of these stoichiometric clusters may be due to the presence of radical oxygen centers (W-O•) with elongated metal-oxygen bonds. The unique insights gained into bulk-phase oxidation catalysis through the application of mass spectrometry to cluster reactivity experiments are discussed.catalysis ͉ tungsten oxide ͉ oxygen radical ͉ carbon monoxide ͉ propylene M ass spectrometry has been crucial to the field of cluster research since its inception (1-9). A variety of cluster formation methods, primarily including laser vaporization (LaVa) (10-12), pulsed-arc discharge (PACIS) (13-15), electrospray ionization (ESI) (16), gas aggregation (17-18), and inert gas sputtering (CORDIS) (18) have enabled the creation of both positively and negatively charged as well as neutral gas-phase clusters across a large size range and with diverse elemental composition. The thermodynamic properties of clusters, including bond-dissociation energies (19-21), endothermic-reaction barriers (22), heat capacities (23), and the enthalpy, entropy, and free-energy changes associated with clustering reactions (24, 25), including those composed of hydrogen-bonded and van der Waals systems, have been widely studied, employing both GIB-MS and flow-tube experiments. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR) (26) along with other linear ion trapping techniques (27) have been used to investigate the time-dependent kinetics of cluster molecule reactions, providing insight into reaction mechanisms, activation energies, and reaction intermediates. The structural properties of clusters, including bonding motifs and collision cross-sections have been examined through collision-induced dissociation (CID) (28) and high-pressure drift cell experiments (29). Time-of-flight (TOF) mass spectrometry...

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“…This test was also selected for evaluate the acidity of this family of materials, based on early works (La Ginestra et al 1987;P. Patrono et al 1994).…”

Section: -Butene Isomerization Testmentioning

confidence: 99%

Preparation, characterization and catalytic applications of ZrO2 supported on low cost SBA-15

et al. 2011

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This work presents some applications of ZrO 2 supported over SBA-15 silica as promoter of sulfated zirconia and as support from CuO/CeO 2 catalytic system for preferential oxidation of CO to CO 2 in hydrogen rich streams, used as feed for proton exchange membrane fuel cells (PEMFC). Different amounts of ZrO 2 , from 10 to 30 wt.% were incorporated. These prepared materials were characterized by powder XRD, adsorption-desorption of N 2 at 77 K, transmission and scanning electron microscopy (TEM and SEM) and X-rays photoelectron spectroscopy (XPS). The acidity was studied by thermo-programmed desorption of ammonia (NH 3 -TPD). These materials were tested, after treatment with H 2 SO 4 , by 2-propanol dehydration and 1-butene isomerization catalytic tests. The samples were found quite good catalyst with strong acid sites, the sample with 20 wt.% of ZrO 2 being the better performing sample. Finally this material was successfully used as support for a CuO/CeO 2 system, with 6 wt.% of Cu and 20 wt.% of Ce. The resulting catalyst was tested in the preferential oxidation of CO (CO-PROX) attaining conversions close to 100% and high selectivity to CO 2 .

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Conversion of 1-butene over WO3-TiO2 Catalysts

Cited by 60 publications

References 22 publications

Acidity of titania-supported tungsten or niobium oxide catalystsCorrelation with catalytic activity

Acidity of titania-supported tungsten or niobium oxide catalystsCorrelation with catalytic activity

Cluster reactivity experiments: Employing mass spectrometry to investigate the molecular level details of catalytic oxidation reactions

Preparation, characterization and catalytic applications of ZrO2 supported on low cost SBA-15

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