A Two-Step Transformation of the Magnesium Salt of Phosphomolybdic Acid HMgPMo12O40Supported on Silica

Tatibouët, Jean‐Michel; Montalescot, Christelle; Brückman, K.; Haber, J.; Che, M.

doi:10.1006/jcat.1997.1693

Cited by 37 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This assignment is in agreement with the results obtained from the Mg salt of HPMo supported on silica. 22 The continuous weight change up to about 708 K without any plateau indicates the absence of a steady state as already found for unsupported HPMo. Since around 708 K there is no well-defined exothermic peak, it is probable that HPA was partly destroyed due to loss of some constitutional water, similarly to bulk HPMo.…”

Section: Thermogravimetric Analysismentioning

confidence: 92%

Structural Features and Thermal Stability of Titania-Supported 12-Molybdophosphoric Heteropoly Compounds

Damyanova

Fierro

1998

Chem. Mater.

View full text Add to dashboard Cite

The structure and thermal decomposition of unsupported and titania-supported 12-phosphoromolybdic acid (HPMo) and its Co and Ni salts have been studied by different techniques including X-ray diffraction, thermogravimetric analysis, FT-infrared, Raman, and X-ray spectroscopic techniques. The transformation of heteropoly anion of bulk HPMo begins at a temperature lower than for its TiO 2 -supported counterpart with the formation of a mixture of R-and -MoO 3 . In the thermal transformation of TiO 2 -supported HPMo, two steps have been identified. The intermediate species formed between the hydrated form of the heteropoly compound and the crystallized molybdenum oxides display the same nuclearity and composition as that of the Keggin precursor. The stability of the HPA supported on titania increases due to the anion-support interaction and this is even enhanced in the Co-and Ni-exchanged homologues.

show abstract

Section: Thermogravimetric Analysismentioning

confidence: 92%

Structural Features and Thermal Stability of Titania-Supported 12-Molybdophosphoric Heteropoly Compounds

Damyanova

Fierro

1998

Chem. Mater.

View full text Add to dashboard Cite

show abstract

“…In order for scientists to utilize effectively bulk HPAs with low specific surface areas (1-5 m 2 /g), the preparation of supported HPA catalysts is indispensable [3]. Although the catalytic activity of supported HPAs was affected by the type of carrier, the HPA loading and the conditions of pretreatment, a number of studies have focused on the thermal stability of HPAs on supports [5,[7][8][9]. Consequently, SiO 2 [5,7], active carbon [9] and acidic ionexchanged resin [3] were suitable supports and especially SiO 2 was preferable.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal synthesis of molybdenum oxide catalyst: Heteropoly acids encaged in US-Y

Tran

Ohkita

Mizushima

et al. 2005

Applied Catalysis A: General

View full text Add to dashboard Cite

“…This phase is result of the aggregation of oxides species originated from the HPC precursor [15]. From this point of view, we can expect that a well-dispersed precursor species will lead to a well-dispersed oxide phase after thermal decomposition of the HPC.…”

Section: Introductionmentioning

confidence: 99%

Support effect on the properties of iron–molybdenum hydrodesulfurization catalysts

et al. 2006

View full text Add to dashboard Cite

Two series of Mo and Fe containing catalysts have been prepared over alumina and titania supports using H 3 PMo 12 O 40 heteropolyacid (HPMo) and Fe salt of HPMo. Catalysts have been characterized by BET, SEM, IR, TPR, XPS methods and by their HDS activity in the reaction of thiophene conversion. The TiO 2 -supported catalysts with low Mo concentration (6 wt%) show higher HDS activity than the catalyst with 12 wt% Mo. Iron promoting effect (Fe/Mo $ 0.1) is observed with both, the aluminaand titania-supported catalysts. Iron supported over alumina increases Mo reducibility and decreases it on TiO 2 -supported catalysts. Compared to alumina-supported catalysts, the TiO 2 -supported catalysts show higher surface concentration of Mo 6+ and Mo 5+ in octahedral coordination -Mo(Oh). Iron increases the Mo(Oh) concentration even more. After sulfidation the Fe-containing catalysts show formation of different Mo valence states (Mo 4+ , Mo 5+ , Mo 6+ ), Fe-P, Mo-P and/or Fe-Mo-P bonds, which affect the HDS catalytic activity.

show abstract

A Two-Step Transformation of the Magnesium Salt of Phosphomolybdic Acid HMgPMo12O40Supported on Silica

Cited by 37 publications

References 0 publications

Structural Features and Thermal Stability of Titania-Supported 12-Molybdophosphoric Heteropoly Compounds

Structural Features and Thermal Stability of Titania-Supported 12-Molybdophosphoric Heteropoly Compounds

Hydrothermal synthesis of molybdenum oxide catalyst: Heteropoly acids encaged in US-Y

Support effect on the properties of iron–molybdenum hydrodesulfurization catalysts

Contact Info

Product

Resources

About