Studies of the hydrogen held by solids XXVI. Proton resonance from alumina and molybdena-alumina catalysts

Cirillo, Albenzio; Dollish, Francis R.; Hall, W. Keith

doi:10.1016/0021-9517(80)90467-4

Cited by 21 publications

References 11 publications

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Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl₂O₃ catalysts

Silvy

Beuken

Fierro

et al. 1986

Surface & Interface Analysis

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The structural changes produced during the reduction by H2 at different temperatures (300–800°C range) of a commercial Co‐Mo/γAl2O3 hydrodesulphurization catalyst have been investigated by x‐ray photoelectron spectroscopy (XPS), ion scattering spectroscopy (ISS) and infrared (IR) of absorbed NO, as a probe‐molecule. In all samples, different cobalt phases are observed. A fraction of cobalt interacts with the alumina support (CoAl2O4‐like, species which was reducible only at the highest temperatures) and another fraction forms a phase interacting with the molybdenum atoms (species easily reducible at moderate temperatures). XPS and ISS results indicated that, at reduction temperatures above 600°C, several effects are produced: (a) an increase of metallic cobalt, (b) a decrease of CoAl2O4 concentration and simultaneous crystallization of MoO2 species, and (c) a decrease of the molybdenum dispersion. From the IR spectra of NO probe chemisorbed on reduced catalyst at 800°C, it was concluded that the slight increase of the Co0 exposure could be due to reduction of CoAl2O4‐like species.

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Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl₂O₃ catalysts

Silvy

Beuken

Fierro

et al. 1986

Surface & Interface Analysis

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Surface microstructure investigation of calcined θ‐Al₂O₃‐supported molybdena catalyst

Zaki

Ismail

Fahim

1986

Surface & Interface Analysis

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Samples of 8-and a-Al,03-supported molybdena catalyst of various loading levels (0.5-16 wt% MOO,) were prepared by impregnation of the support from a dilute aqueous solution (at pH 6) of ammonium paramolybdate. After drying at 8 1 D "C, they were calcined a t 550 "C for 16 h. The effect of support nature and Mo loading level on surface microstnictural characteristics, namely pbysicochemical identity of the supported Mo-0 species and consequent textural modifications of the calcination products thus yielded, were investigated by means of differential thermal and therrnogravimetric analyses, x-ray diffraction, infrared spectroscopy, scanning electron microscopy and N, adsorption. The results obtained show that during the thermal treatment of the impregnated samples the adsorbed paramolybdate anions interact preferentially with the thermally most stable surface OH groups (relatively most basic) which reside at the interior and/or entrances of fine pores of the support. They further show that 8-Al,03 stabilizes the mollybdates loaded at up to 12% level in monolayer-like structures, however a-Al,03 does not do likewise giving waiy to the formation of AI,(MoO& and bulk MOO, at a loading level as low as 4%.~

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Stoichiometry of Reaction between MoO3and OH Groups of Alumina

Vı́t

Zdražil

1997

Journal of Catalysis

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Studies of the hydrogen held by solids XXVI. Proton resonance from alumina and molybdena-alumina catalysts

Cited by 21 publications

References 11 publications

Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl₂O₃ catalysts

Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl₂O₃ catalysts

Surface microstructure investigation of calcined θ‐Al₂O₃‐supported molybdena catalyst

Stoichiometry of Reaction between MoO3and OH Groups of Alumina

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Studies of the hydrogen held by solids XXVI. Proton resonance from alumina and molybdena-alumina catalysts

Cited by 21 publications

References 11 publications

Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl2O3 catalysts

Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl2O3 catalysts

Surface microstructure investigation of calcined θ‐Al2O3‐supported molybdena catalyst

Stoichiometry of Reaction between MoO3and OH Groups of Alumina

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Product

Resources

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Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl₂O₃ catalysts

Surface investigation, by XPS, ISS and IR spectroscopy of adsorbed NO, of the structural changes occurring during the reduction of Co‐Mo/γAl₂O₃ catalysts

Surface microstructure investigation of calcined θ‐Al₂O₃‐supported molybdena catalyst