Selective isomerization of alkanes on supported tungsten oxide acids

Iglesia, Enrique; Barton, David G.; Soled, S.; Miseo, S.; Baumgartner, Joseph E.; Gates, William E.; Fuentes, Gustavo A.; Meitzner, G.

doi:10.1016/s0167-2991(96)80264-3

Cited by 212 publications

(225 citation statements)

References 21 publications

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“…Other works [30] on WO3eSiO2 systems have reported a dispersion capability of WO3 on mesoporous silica of only 0.5 W þ6 nm -2 . Our data suggest that the interaction of tungsten oxide with pure silica may be weaker than that of tungsten oxide with aluminum-containing silica, in agreement with the above mentioned works [29,30]. Here, this different interaction was indeed mirrored by the different dispersion of the tungsten oxide species on the Al-free and Al-containing silica supports, as suggested by the XRD and Raman analyses (vide infra, Fig.…”

Section: Structural Featuressupporting

confidence: 89%

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Synthesis of tungsten carbide on Al-SBA-15 mesoporous materials by carburization

Álvarez

Chimentão

Tichit

et al. 2016

Microporous and Mesoporous Materials

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a b s t r a c t Aluminum was incorporated into SBA-15 supports at molar ratios Si/Al ¼ 10 and 2 by the pH-adjusting method. The calcined mesoporous Al-SBA-15 supports, as well as the Al-free SBA-15 support, were impregnated with ammonium paratungstate ((NH4)10[H2W12O42]4H2O) aqueous solution. Tungsten carbide (W2C) was synthesized by temperature programmed carburization (TPC) from the WO3 supported on Al-SBA-15 and SBA-15 in a flow of CH4/H2. These resultant materials were characterized by powder X-ray diffraction (XRD), N2 adsorption/desorption, 27 Al NMR and Raman spectroscopies, and transmission electron microscopies (TEM and HRTEM). W2C species were obtained after the carburization process in all the materials. The mesoporous structure of the SBA-15 supports was preserved at all synthesis steps. XRD and TEM analyses revealed that the introduction of aluminum species into the SBA-15 greatly enhanced the dispersion of WO3 and W2C phases during the calcination and carburization steps, respectively. In situ XRD measured during the carburization in a synchrotron facility provided further details of the reduction of tungsten trioxide species as a function of temperature. The presence of aluminum in the SBA-15 notably affected the distribution and the reduction temperature of the tungsten oxide species.

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Section: Structural Featuressupporting

confidence: 89%

“…XPS studies on WO3eAl2O3 by Iglesia et al [29] provide an estimation of the maximum planar packing density of WO3 species as 3.7 W þ6 nm -2 . Other works [30] on WO3eSiO2 systems have reported a dispersion capability of WO3 on mesoporous silica of only 0.5 W þ6 nm -2 .…”

Section: Structural Featuresmentioning

confidence: 99%

Synthesis of tungsten carbide on Al-SBA-15 mesoporous materials by carburization

Álvarez

Chimentão

Tichit

et al. 2016

Microporous and Mesoporous Materials

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“…Among the zirconia-supported systems, tungsten oxidebased catalysts, have received a great deal of attention, because they are attractive as catalysts for the reactions of isomerization of light alkanes [1][2][3][4][5][6][7] and selective catalytic reduction of nitrogen oxides with hydrocarbons [8,9]. The catalytic properties of these oxide systems depend strongly on the WO x surface density, which can be varied by changing the content of the active oxide phase and the catalyst treatment temperature [1][2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…The catalytic properties of these oxide systems depend strongly on the WO x surface density, which can be varied by changing the content of the active oxide phase and the catalyst treatment temperature [1][2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…The WO x /ZrO 2 catalysts are usually prepared by impregnating hydrous zirconium oxyhydroxide, ZrO x (OH) 4-2x , with aqueous solutions of ammonium metatungstate (AMT) [2][3][4][6][7][8][9][10][11][12][13] or by coprecipitation [5] followed by calcination in air. In general, the equilibrium adsorption procedures allow better dispersion of the active phase and this method has been used by Valigi and coworkers [13][14][15][16] to prepare various zirconia-based catalysts starting from amorphous ZrO x (OH) 4-2x .…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopic characterization of tungstated zirconia prepared by equilibrium adsorption from hydrogen peroxide solutions of tungsten(VI) precursors

Kantcheva

Koz

2007

J Mater Sci

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. The starting material is amorphous zirconium oxyhydroxide. The maximum W densities obtained are larger than that reported in the literature for systems synthesized by the same method using aqueous non-peroxide solutions. In the case of the metatungstate precursor, this increase is attributed to the generation of additional anchoring sites by interaction between the amorphous support and H 2 O 2 . The high uptake achieved when the peroxo complex is used as a precursor is a result of both the ZrO x (OH) 4-2x -H 2 O 2 interaction and low nuclearity of the adsorbing anion. The materials are characterized by XRD, DR-UV-vis, Micro-Raman and FT-IR spectroscopy. The surface acidities of samples with identical W loading prepared by equilibrium adsorption from the [H 2 W 12 O 40 ] 6--H 2 O 2 system and by impregnation with aqueous solution of ammonium metatungstate are investigated by FT-IR spectroscopy of CO adsorbed at 80 K.

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Designer Nanomaterials for the Production of Energy and High Value‐Added Chemicals

Luque

2010

Ideas in Chemistry and Molecular Sciences

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Selective isomerization of alkanes on supported tungsten oxide acids

Cited by 212 publications

References 21 publications

Synthesis of tungsten carbide on Al-SBA-15 mesoporous materials by carburization

Synthesis of tungsten carbide on Al-SBA-15 mesoporous materials by carburization

Spectroscopic characterization of tungstated zirconia prepared by equilibrium adsorption from hydrogen peroxide solutions of tungsten(VI) precursors

Designer Nanomaterials for the Production of Energy and High Value‐Added Chemicals

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