Characterization of MoO3/SiO2 and WO3/SiO2 catalysts by low-temperature oxygen chemisorption, 1H MAS NMR, and XRD techniques

Reddy, B. M.; Rao, K. Sai Prasad; Мастихин, В. М.

doi:10.1016/0021-9517(88)90284-9

Cited by 15 publications

(1 citation statement)

References 14 publications

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“…The specific surface areas and oxygen uptake values of the catalysts are presented in Table . Previous studies , used T red = 773 K and T ads = 77 K, followed by evacuation and readsorption at 195 K. These conditions were evaluated by Rodrigo et al, who concluded that O 2 chemisorption under these conditions does not provide a quantitative determination of Mo dispersion because a fraction of the reduced Mo is in the bulk. It has been shown that oxygen chemisorption sites are easily generated at very mild reduction conditions, such as those employed in this study .…”

Section: Resultsmentioning

confidence: 99%

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La₂O₃-Stabilized Tetragonal ZrO₂

2003

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A series of molybdenum oxide catalysts with Mo loadings in the range 2.5−12.5 wt % Mo supported on La2O3-stabilized ZrO2 was prepared by impregnation. X-ray diffraction results of the catalysts showed the diffraction patterns of crystalline MoO3 from 10 wt % Mo. Dispersion of molybdena was determined by the oxygen chemisorption method, and it was found to decrease with an increase in Mo loading due to formation of MoO3 crystallites at higher Mo loadings. Temperature-programmed reduction results suggest that the reducibility is found to decrease with Mo loading as a result of the decrease in dispersion. The acidity of the catalysts was found to increase with Mo loading, and the activity of the catalysts also found to increase with the increase in Mo loading up to 7.5 wt % Mo loading. Laser Raman spectra of the catalysts show the Raman bands due to MoO3 from 7.5 wt % Mo at 819 and 997 cm-1. At lower Mo loadings, highly dispersed species were observed. The catalytic properties were evaluated during the ammoxidation of toluene to benzonitrile and were related to the oxygen chemisorption sites on the support surface.

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Section: Resultsmentioning

confidence: 99%

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La₂O₃-Stabilized Tetragonal ZrO₂

2003

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Dispersion and Thermal Stability of MoO3on TiO2-ZrO2Mixed Oxide Support

Reddy

Chowdhury

1998

Journal of Catalysis

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Tungsta supported on zirconia and alumina catalysts: temperature-programmed desorption/reaction of methanol and pyridine DRIFTS studies

et al. 1996

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Characterization of MoO3/SiO2 and WO3/SiO2 catalysts by low-temperature oxygen chemisorption, 1H MAS NMR, and XRD techniques

Cited by 15 publications

References 14 publications

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La₂O₃-Stabilized Tetragonal ZrO₂

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La₂O₃-Stabilized Tetragonal ZrO₂

Dispersion and Thermal Stability of MoO3on TiO2-ZrO2Mixed Oxide Support

Tungsta supported on zirconia and alumina catalysts: temperature-programmed desorption/reaction of methanol and pyridine DRIFTS studies

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Characterization of MoO3/SiO2 and WO3/SiO2 catalysts by low-temperature oxygen chemisorption, 1H MAS NMR, and XRD techniques

Cited by 15 publications

References 14 publications

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La2O3-Stabilized Tetragonal ZrO2

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La2O3-Stabilized Tetragonal ZrO2

Dispersion and Thermal Stability of MoO3on TiO2-ZrO2Mixed Oxide Support

Tungsta supported on zirconia and alumina catalysts: temperature-programmed desorption/reaction of methanol and pyridine DRIFTS studies

Contact Info

Product

Resources

About

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La₂O₃-Stabilized Tetragonal ZrO₂

Structure and Reactivity of Molybdenum Oxide Catalysts Supported on La₂O₃-Stabilized Tetragonal ZrO₂