Structure and properties of a supported MoO3–SBA-15 catalyst for selective oxidation of propene

Ressler, Thorsten; Walter, Anke; Huang, Zhigao; Bensch, Wolfgang

doi:10.1016/j.jcat.2007.12.012

Cited by 59 publications

(40 citation statements)

References 16 publications

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“…11) was much larger than in the case of 1. Similarly, NH 3 Then, in the final decomposition step (370-420 °C) the h-MoO 3 disappeared, the o-MoO 3 became more crystalline accompanied by an exothermic heat effect (exothermic DTA peak at 400 °C) and also the Mo 4 O 11 phase was detected to some extent, just as in the case of 1. Accordingly, the remaining was was a bit lower (73.3 %) than what expected for pure MoO 3 (73.5 %)…”

Section: Thermal Decomposition Of 2 In Nmentioning

confidence: 91%

“…In the third, endothermic decomposition step (270-370 °C) the parallel evolution of NH 3 In the last step (370-400 °C) in a slightly exothermic reaction the amount of o-MoO 3 increased (81.5 and 81.2 % theoretical and measured remaining mass). The h-MoO 3 phase disappeared and a partially reduced molybdenum oxide, i.e.…”

Section: % Theoretical and Measured Remaining Mass) The N-h And O-h mentioning

confidence: 99%

“…MoOx catalysts have applications in various catalytic reactions, e.g. partial oxidation for light alkenes, hydrotreating, hydrodenitrogenation, or hydrodesulfurisation [1][2][3][4][5]. Molybdenum carbide is also applied as a catalyst for e.g.…”

Section: Introductionmentioning

confidence: 99%

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Thermal decomposition of ammonium molybdates

Kovács

Hunyadi

Lucena

et al. 2016

J Therm Anal Calorim

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The thermal behavior of ammonium molybdates, i.e. (NH 4 ) 6 Mo 7 O 24 •4H 2 O (1) and (NH 4 ) 2 MoO 4 (2), was studied in inert (N 2 ) and oxidizing (air) atmospheres by TG/DTA-MS, XRD, FTIR and SEM. The thermal decomposition sequence of 2 had similarities to 1; however, there were significant differences as well. When both of them were annealed, NH 3 and H 2 O were released parallel, and in air the asevolved NH 3 was burnt partially into NO and N 2 O. In both atmospheres, while 1 decomposed in four steps, the thermal decomposition of 2 involved 5 steps. In the case of 1, the intermediate products were Most decomposition steps were endothermic, except for the last step around 400 °C, where crystallization from the residual amorphous phase had an exothermic heat effect. In addition, the combustion of NH 3 also changed the DTA curve into exothermic in some cases. The morphology of the final products was characterized by 1-5 m sheet-like particles, except for annealing 2 in N 2 , when 0.5-1 m thick and 5-10 m long needle-shaped particles were detected.

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Section: Thermal Decomposition Of 2 In Nmentioning

confidence: 91%

Section: % Theoretical and Measured Remaining Mass) The N-h And O-h mentioning

confidence: 99%

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Thermal decomposition of ammonium molybdates

Kovács

Hunyadi

Lucena

et al. 2016

J Therm Anal Calorim

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“…This prompted us to investigate the mechanistic features of this reaction in presence of MB and as a function of the amount of Mo 5+ -O-Mo 6+ bridges. In fact, by treating some metal oxides like MoO 3 , WO 3 , and Cr 2 O 3 and high temperature (T > 180 o C) in the absence of oxygen, it is possible to remove lattice oxygen and this can affect their reactivity [15]. This procedure was also successfully employed in the gas phase oxidation of cyclohexane using MoO 3 without collapse of the metal oxide framework [16].…”

Section: Introductionmentioning

confidence: 99%

Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

et al. 2015

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Molybdenum blue (MB), is a polyoxometalate with a nanoring structure comprising Mo 5+ -OMo 6+ bridges, which is active for the catalytic oxidation of cyclohexane to cyclohexanol and cyclohexanone. However, little is known about the mechanistic features responsible of this catalytic activity. In the present work, the Mo 5+ -O-Mo 6+ moieties embedded in the MB nanoring structure were characterized using diffuse reflectance-UV-Visible spectroscopy and solid state EPR spectroscopy. The amount of Mo 5+ centres was then varied by thermal treatment of the polyoxometalate in the absence of oxygen, and the resultant effect on the catalytic activity was investigated. It was observed that, an increased amount of Mo 5+ centres preserved the conversion of cyclohexane (ca. 6%) but led to a loss of selectivity to cyclohexanol giving cyclohexanone as the major product, and the simultaneous formation of adipic acid. To rationalise these results the catalysts were studied using EPR spin trapping to investigate the decomposition of cyclohexyl hydroperoxide (CHHP), a key intermediate in the oxidation process of cyclohexane. This analysis showed that CHHP has to be bound to the MB surface in order to explain its catalytic activity and product distribution.

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“…The development of composite coatings based on transition metal oxides, including molybdenum oxide compounds with a wide range of practical application [145][146][147][148] is a promising trend of surface modification.…”

Section: Catalytically-active Composite Materials Based On Transitionmentioning

confidence: 99%

The use of transient electrolysis in the technology of oxide composite nanostructured materials: review

Bespalova¹,

Храменкова²

2016

Nanosystems: Phys. Chem. Math.

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The available experimental material relating to the patterns of formation and properties of functional nanostructured transition metal oxide (Mo, Co, Mn, Ni, Fe, V) composite materials is reviewed. Advanced coatings are considered those whose formation method are simple and do not require high energy costs, expensive equipment and permit the creation of materials with desired physical and chemical properties in a specified manner. In this review, the priority of oxide composite nanostructured materials technology is given to a transient electrolysis method based on the analysis of a data set that demonstrates its advantages. The results are presented for a number of studies aimed at identifying and analyzing the nature and regularities of processes that take place when obtaining oxide composite nanostructured materials using transient electrolysis methods.

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Structure and properties of a supported MoO3–SBA-15 catalyst for selective oxidation of propene

Cited by 59 publications

References 16 publications

Thermal decomposition of ammonium molybdates

Thermal decomposition of ammonium molybdates

Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

The use of transient electrolysis in the technology of oxide composite nanostructured materials: review

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