Selective oxidation of methanol on iron molybdate catalysts and the effects of surface reduction

House, Matthew Peter; Carley, Albert Frederick; Bowker, Michael

doi:10.1016/j.jcat.2007.09.005

Cited by 65 publications

(62 citation statements)

References 13 publications

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“…9,13,14 To summarise, the reactor was a tubular reactor, 1/4 00 OD, operating in TPD (temperature programmed desorption) mode with a continuous flow of helium at a flowrate of 30 mL min…”

Section: Methodsmentioning

confidence: 99%

Selectivity determinants for dual function catalysts: applied to methanol selective oxidation on iron molybdate

Bowker

House

Alshehri

et al. 2015

Catalysis, Structure & Reactivity

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Evolution of the IRAS spectrum with temperature after adsorbing methanol at room temperature. The bands at 2930 and 2820 cm 21 are due to the methoxy species C -H stretches, while that at 2870 is due to the formate.Here, we report a simple, quantitative model to describe the behaviour of bi-cationic oxide catalysts, in terms of selectivity variation as a function of increased loading of one cation into a sample of the other. We consider its application to a particular catalytic system, namely the selective oxidation of methanol, which proceeds with three main C1 products, namely CO 2 , CO, and H 2 CO. The product selectivity varies in this order as Mo is added in increasing amounts to an iron oxide catalyst, and the product selectivity is determined by the distribution of dual sites and single sites of each species.

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“…9,13,14 To summarise, the reactor was a tubular reactor, 1/4 00 OD, operating in TPD (temperature programmed desorption) mode with a continuous flow of helium at a flowrate of 30 mL min…”

Section: Methodsmentioning

confidence: 99%

Selectivity determinants for dual function catalysts: applied to methanol selective oxidation on iron molybdate

Bowker

House

Alshehri

et al. 2015

Catalysis, Structure & Reactivity

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show abstract

“…House et al [22,41] have exploited TPD and pulsed flow studies to investigate this reduction phenomenon in more detail. The reaction and reduction of iron molybdate (Mo:Fe = 2.2:1) with methanol feedstock under anaerobic conditions was adopted.…”

Section: Initial Investigations Into the Mechanism And Reaction Sitementioning

confidence: 99%

Catalysts for the Selective Oxidation of Methanol

2016

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Abstract:In industry, one of the main catalysts typically employed for the selective oxidation of methanol to formaldehyde is a multi-component oxide containing both bulk Fe 2 (MoO 4 ) 3 and excess MoO 3 . It is thought that the excess MoO 3 primarily acts to replace any molybdenum lost through sublimation at elevated temperatures, therefore preventing the formation of an unselective Fe 2 O 3 phase. With both oxide phases present however, debate has arisen regarding the active component of the catalyst. Work here highlights how catalyst surfaces are significantly different from bulk structures, a difference crucial for catalyst performance. Specifically, Mo has been isolated at the surface as the active surface species. This leaves the role of the Fe in the catalyst enigmatic, with many theories postulated for its requirement. It has been suggested that the supporting Fe molybdate phase enables lattice oxygen transfer to the surface, to help prevent the selectivity loss which would occur in the resulting oxygen deficit environment. To assess this phenomenon in further detail, anaerobic reaction with methanol has been adopted to evaluate the performance of the catalyst under reducing conditions.

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“…Some discussion on this point is given in the recent review by Soares et al [1] though it mainly focuses on the bulk properties of iron molybdate and its reactivity. Iron molybdate catalysts are used commercially for the selective oxidation of methanol to formaldehyde in aerobic conditions; they are very successful materials for this purpose, showing selectivities in excess of 90% at greater than 90% conversion [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Surface Segregation in Iron Molybdate Catalysts

2008

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The high selectivity of iron molybdate catalysts for the production of formaldehyde from methanol is somewhat surprising in view of the very different behaviour of the individual oxides of Fe and Mo for this reaction. The former, on its own, is a complete combustor of methanol, whereas the latter is highly selective. Here we use STEM (scanning transmission electron microscopy) at high resolution to image the surface of small particles of the catalyst and to show that this high selectivity is due to the dominance of the surface region by molybdenum oxide.

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Selective oxidation of methanol on iron molybdate catalysts and the effects of surface reduction

Cited by 65 publications

References 13 publications

Selectivity determinants for dual function catalysts: applied to methanol selective oxidation on iron molybdate

Selectivity determinants for dual function catalysts: applied to methanol selective oxidation on iron molybdate

Catalysts for the Selective Oxidation of Methanol

Surface Segregation in Iron Molybdate Catalysts

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