Catalytic Behavior of Unsupported and Heteropolysalt-Supported H3+PV Mo12−O40 Heteropolyacids in the Test Reaction of CH3OH Oxidation

Brückman, K.; Tatibouët, Jean‐Michel; Che, M.; Serwicka, Ewa M.; Haber, J.

doi:10.1006/jcat.1993.1040

Cited by 66 publications

(27 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The methanol oxidation TOF was found to essentially be independent of the surface coverage of the surface redox sites which suggests that this oxidation reaction requires only one surface redox site to proceed. A similar conclusion was also reached for methanol oxidation over model Keggin metal oxide catalysts (15,16). The methanol oxidation TOF was also not influenced by the presence of other non-reducible surface metal oxide species in the two-dimensional overlayer (e.g., oxides of W, Nb, Si and S) and is consistent with the conclusion that only one redox site is required for this reaction (14).…”

Section: Catalytic Activitysupporting

confidence: 83%

The Activity and Selectivity Properties of Supported Metal Oxide Catalysts During Oxidation Reactions

Wachs

Deo

Jehng

et al. 1996

ACS Symposium Series

View full text Add to dashboard Cite

Structure-reactivity studies involving model supported metal oxide catalysts reveal that the efficiency of a particular selective oxidation reaction depends on the specific supported metal oxide species, the coverage of the surface metal oxide species, the oxide support, and the presence of secondary metal oxide additives. In situ Raman spectroscopy, activity, and selectivity of the partial oxidation of methanol, alkanes, and the selective catalytic reduction of NO with ammonia are discussed with respect to the above factors for supported metal oxide catalysts.Supported metal oxide catalysts are extensively employed in the petrochemical and pollution control industries as oxidation catalysts. For example, titania supported vanadia catalysts are used for the selective oxidation of o-xylene to phthalic anhydride, ammoxidation of aromatic methyl groups and the selective catalytic reduction (SCR) of NO x with ammonia. The active redox components (V, Mo, Cr or Re) of supported metal oxide catalysts are present as two-dimensional metal oxide overlayers on the high surface area oxide supports (e.g., titania, alumina, silica, niobia, zirconia, etc.). Such supported metal oxide catalysts are also ideal model systems to study the fundamental aspects of selective oxidation reactions because the active surface redox sites can be molecularly characterized with in situ Raman, IR, solid state NMR, DRS and EXAFS/XANES. Furthermore, the environment around the active redox sites can also be varied by changing the surface metal oxide coverage, changing the specific oxide support or by the addition of secondary metal oxide additives (e.g., oxides of W, Nb, P, etc.) to the two-dimensional overlayer. In the present investigation, Raman

show abstract

Section: Catalytic Activitysupporting

confidence: 83%

The Activity and Selectivity Properties of Supported Metal Oxide Catalysts During Oxidation Reactions

Wachs

Deo

Jehng

et al. 1996

ACS Symposium Series

View full text Add to dashboard Cite

show abstract

“…Bimolecular CH 3 OH dehydration oxidation has been studied extensively on Keggin clusters of varying composition and catalytic functions [1,2,[4][5][6][7] We have recently reported the one-step selective synthesis of DMM via methanol oxidation at low temperatures (400-500 K) on SiO 2 -supported H 3+n PV n Mo 12−n O 40 (n = 0-4) Keggin clusters [8]; this reaction proceeds via bifunctional pathways requiring acid and redox sites. The controlled titration or dehydroxylation of Brønsted acid sites by thermal treatment or by permanent titration with organic bases, such as pyridine, led to a selective decrease in DME formation rates, without significant changes in the rates of DMM synthesis [8,9].…”

Section: Introductionmentioning

confidence: 99%

Effects of support on bifunctional methanol oxidation pathways catalyzed by polyoxometallate Keggin clusters

Liu

2004

Journal of Catalysis

View full text Add to dashboard Cite

“…Hydrated (undecomposed) forms of H3PMol2040 with the Keggin structure are known to be pure Br6nsted acids [19,20]. The thermal decomposition of such compounds results in the loss of Br6nsted acidity [17][18][19].…”

Section: Resultsmentioning

confidence: 79%

Mechanism of formic acid decomposition on P−Mo heteropolyacid

Popova

Захаров

Андрушкевич

1999

React Kinet Catal Lett

View full text Add to dashboard Cite

Abs~a~Hydrated (tmdecomposed) form of heteropolyacid H3PM012040/SiO2 exhibits a higher activity in the formic acid decomposition than the corresponding dehydrated sample. The formic acid decomposition takes place on strong Br6nsted acid sites of the heteropolyacid. Ab initio SCF MO LCAO method was used for the calculation of the electronic state of two surface complexes of HCOOH molecule (S1 and $2) coordinated to a proton I~. The SI complex is formed by proton addition to the carbonyl oxygen, whereas the $2 complex is formed by proton addition to the oxygen atom of the C-O-H fragment of HCOOH, The selective weakening of the C-O bond and localization of the positive charge on the (O=C-IT) fragment in the protonated complex $2 are favorable for the decomposition of formic acid to CO and H20.

show abstract

Catalytic Behavior of Unsupported and Heteropolysalt-Supported H3+PV Mo12−O40 Heteropolyacids in the Test Reaction of CH3OH Oxidation

Cited by 66 publications

References 0 publications

The Activity and Selectivity Properties of Supported Metal Oxide Catalysts During Oxidation Reactions

The Activity and Selectivity Properties of Supported Metal Oxide Catalysts During Oxidation Reactions

Effects of support on bifunctional methanol oxidation pathways catalyzed by polyoxometallate Keggin clusters

Mechanism of formic acid decomposition on P−Mo heteropolyacid

Contact Info

Product

Resources

About