Methanol Selective Oxidation to Formaldehyde over Iron‐Molybdate Catalysts

Soares, Ana Paula V.; Portela, M.F.; Kiennemann, A.

doi:10.1081/cr-200049088

Cited by 209 publications

(181 citation statements)

References 74 publications

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“…The Fe 2 (MoO 4 ) 3 phase is generally considered to be the primary active phase, and, under standard conditions, a partial reduction of this phase occurs on reaction with methanol, resulting in the formation of formaldehyde, inactive b-FeMoO 4 and MoO 3 [14]. These are then rapidly regenerated to Fe 2 (MoO 4 ) 3 by oxygen in the gas stream completing the catalytic cycle.…”

Section: Introductionmentioning

confidence: 99%

“…However, under these conditions sublimation of molybdenum can occur, particularly at reactor hot spots and, if there is not sufficient excess molybdenum in the catalyst (i.e. if Mo/Fe is not greater than 1.5), breakdown to oxides occurs [13,[15][16][17][18]: Many authors believe the redox process occurs via a Mars-Van Krevelen type mechanism, [14,[19][20][21]. This mechanism is supported by kinetic studies and experimental works indicating rapid diffusion of bulk oxygen to the catalyst surface [22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

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A Combined Multi-Technique In Situ Approach Used to Probe the Stability of Iron Molybdate Catalysts During Redox Cycling

et al. 2009

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A setup combining a number of techniques (WAXS, XANES and UV-Vis) has been used to probe the stability of an iron molybdate catalyst during redox cycling. The catalyst was first reduced under anaerobic methanol/ helium conditions, producing formaldehyde and then regenerated using air. Although in this test-case the catalyst and conditions differ from that of a commercial catalyst bed we demonstrate how such a setup can reveal new information on catalyst materials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Combined Multi-Technique In Situ Approach Used to Probe the Stability of Iron Molybdate Catalysts During Redox Cycling

et al. 2009

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“…At present, Ag and a mixed Fe-Mo oxide have been used as industrial catalysts for this reaction (e.g., see [3] and references therein). Despite substantial efforts in research for these catalysts, eminent issues still need to be overcome, namely the minimization of byproduct formation.…”

Section: Introductionmentioning

confidence: 99%

Relating methanol oxidation to the structure of ceria-supported vanadia monolayer catalysts

Abbott

Uhl

Baron

et al. 2010

Journal of Catalysis

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Abstract.Vanadia "monolayer"-type catalysts supported on reducible oxides such as ceria previously have shown high activity for the selective oxidation of alcohols. Here, a model system consisting of vanadia particles deposited on well-ordered CeO 2 (111) thin films has been employed. Scanning tunneling microscopy (STM), photoelectron spectroscopy (PES), and infrared reflection absorption spectroscopy (IRAS) were used to characterize the VO x /CeO 2 surface as a function of vanadia loading. The formation of isolated monomeric species as well as two-dimensional vanadia islands that wet the ceria support was directly observed by STM. The vanadia species exhibit V in a +5 oxidation state and expose vanadyl (V=O) groups with stretching vibrations that blue -shift from ~1005 cm -1 , to ~1040 cm -1 with increasing coverage.Temperature programmed desorption (TPD) of methanol revealed three peaks for formaldehyde production. One is correlated with reactivity on the ceria support (565-590 K). Another is correlated with reactivity on large vanadia particles (475-505 K) similar to that previously observed on vanadia/silica and vanadia/alumina model systems. A low temperature reaction pathway (~370 K) is observed at low coverage, which is assigned to the reactivity of isolated vanadia species surrounded by a reduced ceria surface. It is concluded that strong support effects reported in the literature for the real catalysts are likely related to the stabilization of small vanadia clusters by reducible oxide supports.

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“…Molybdenum is extensively used as a key component in mixed oxide catalysts like for instance iron-molybdate catalysts for the selective oxidation of methanol to formaldehyde [1]. It is assumed that Mo sites play a relevant role for the reactivity of these systems, but many questions regarding the active sites and the reaction mechanism are still open at present [1].…”

Section: Introductionmentioning

confidence: 99%

“…It is assumed that Mo sites play a relevant role for the reactivity of these systems, but many questions regarding the active sites and the reaction mechanism are still open at present [1]. Pure MoO 3 exhibits good activity for several reactions like the partial oxidation of methanol to formaldehyde [2] and the partial oxidation of propene [3].…”

Section: Introductionmentioning

confidence: 99%

LEED I/V determination of the structure of a MoO3 monolayer on Au(111): Testing the performance of the CMA-ES evolutionary strategy algorithm, differential evolution, a genetic algorithm and tensor LEED based structural optimization

2016

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The structure of a thin MoO 3 layer on Au(111) with a c(4×2) superstructure was studied with LEED I/V analysis. As proposed previously (Quek et al, Surf. Sci. 577 (2005) L71), the atomic structure of the layer is similar to that of a MoO 3 single layer as found in regular α-MoO 3 . The layer on Au(111) has a glide plane parallel to the short unit vector of the c(4×2) unit cell and the molybdenum atoms are bridge-bonded to two surface gold atoms with the structure of the gold surface being slightly distorted. The structural refinement of the structure was performed with the CMA-ES evolutionary strategy algorithm which could reach a Pendry R-factor of ∼0.044. In the second part the performance of CMA-ES is compared with that of the differential evolution method, a genetic algorithm and the Powell optimization algorithm employing I/V curves calculated with tensor LEED.

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Methanol Selective Oxidation to Formaldehyde over Iron‐Molybdate Catalysts

Cited by 209 publications

References 74 publications

A Combined Multi-Technique In Situ Approach Used to Probe the Stability of Iron Molybdate Catalysts During Redox Cycling

A Combined Multi-Technique In Situ Approach Used to Probe the Stability of Iron Molybdate Catalysts During Redox Cycling

Relating methanol oxidation to the structure of ceria-supported vanadia monolayer catalysts

LEED I/V determination of the structure of a MoO3 monolayer on Au(111): Testing the performance of the CMA-ES evolutionary strategy algorithm, differential evolution, a genetic algorithm and tensor LEED based structural optimization

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