Catalytic Properties of Supported Molybdenum Oxide Catalysts: In Situ Raman and Methanol Oxidation Studies

Hu, Hangchun; Wachs, Israel E.

doi:10.1021/j100027a035

Cited by 144 publications

(117 citation statements)

References 8 publications

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“…This is in agreement with observations of Hu et al [77] for ZrO 2 supports in their study of supported molybdenum oxide catalysts and is also an indication of zirconia's acid-base properties [78]. All Pt/ZrO 2 samples showed 100% conversion of MeOH when the oxidation reaction was carried out at 260°C accompanied by the disappearance of methyl formate and dimethyl ether.…”

Section: Meoh Oxidation: Activity and Selectivitysupporting

confidence: 92%

Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation: Effect of Pretreatment and Oxidation State on the Activity for Methanol Decomposition and Oxidation

et al. 2009

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The effect of pretreatment conditions on the oxidation state and activity of micelle-synthesized Pt nanoparticles supported on ZrO 2 was studied for methanol decomposition and oxidation reactions. An O 2 -pretreatment is observed to be effective for producing clean, stable, and active nanoparticles. Pt-oxide species formed during such pretreatments were found to have little influence in methanol decomposition reactions due to their tendency to reduce. However, these same species are stable during methanol oxidation and appear to take part in a Mars-van Krevelen-type of process, in which bound-oxygen (nanoparticle shell) may be replenished with oxygen from the gas phase.

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Section: Meoh Oxidation: Activity and Selectivitysupporting

confidence: 92%

Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation: Effect of Pretreatment and Oxidation State on the Activity for Methanol Decomposition and Oxidation

et al. 2009

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“…Prior to methanol oxidation, the dehydrated and fully oxidized surface molybdenum oxide species, Mo (VI), gives rise to Raman bands at 1004, 862, 636 and 520 cm 1 , which are characteristic of polymeric surface molybdenum oxide species. 63 situ studies over 4% MoO 3 /ZrO 2 did not show Raman bands characteristic of reduced surface molybdenum oxide species [ Fig. 7(B)].…”

Section: Methanol Oxidation Reaction Conditionsmentioning

confidence: 99%

Molecular structures of supported metal oxide catalysts under different environments

Bañares

Wachs

2002

J Raman Spectroscopy

356

307

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The use of in situ Raman spectroscopy to study the molecular structures of supported metal oxide catalysts under different environments is reviewed. The molecular structures under ambient (hydrated) and dehydrated conditions are presented. The effect of moisture at elevated temperatures is also presented and discussed with regard to its implications for catalytic phenomena. The molecular structural transformations during C 2 -C 4 lower alkane (LPG) oxidation, methane oxidation, methanol oxidation and selective catalytic reduction of NO with NH 3 reaction conditions are presented. In situ spectroscopy during catalytic reaction with simultaneous activity/selectivity measurement ('operando' spectroscopy) is emphasized owing to its contribution to the fundamental understanding of catalytic performance. The reducibility of the different surface metal oxide species, the relevance of surface coverage (surface monomeric vs polymeric species) and the specific oxide support are discussed when LPG, methane, methanol or hydrogen is the reducing agent. In situ Raman spectroscopy provides molecular-level information about the surface metal oxide species: structures, stability and transformations under different environments. In many cases, the use of complementary spectroscopic techniques results in a more complete understanding of the molecular structure-activity/selectivity relationships for supported metal oxide catalysts.

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“…An activity of these catalysts in the respective reactions was found related with strong acidity possessed by them. It is also found that, the type of support plays an important role on the catalytic properties and for a given reaction the activity and selectivity of the catalyst can be improved by the use of an appropriate support [16]. For example, intrinsic benign characteristics of both titania and zirconia support can be explored fully by using them in combination.…”

mentioning

confidence: 99%

Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

Kemdeo

Sapkal

Chaudhari

2010

Bull. Chem. React. Eng. Catal.

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TiO2-ZrO2 mixed oxide support was prepared and impregnated with 12 wt % MoO3 and calcined at various temperatures. The resultant catalyst systems were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR methods to know the physico-chemical changes occurred in course of thermal treatment. Activities of these catalysts were tested by employing them in the nitration of o-xylene. Mostly, 500 oC calcined catalyst sample was found to be most active for nitration reaction. Catalyst calcined at higher temperatures showed the negative influence on o-xylene conversion and 4-nitro-o-xylene selectivity. Conversion can be correlated with the presence of strong Brönsted acid sites over the catalyst surface whereas change in selectivity was found attributed to the pore diameter of the catalyst. These catalysts also performed satisfactorily, when used for nitration of other aromatics. No use of corrosive sulfuric acid and efficient reusability of the catalyst make the process environmentally friendly and economic. © 2010 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

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Catalytic Properties of Supported Molybdenum Oxide Catalysts: In Situ Raman and Methanol Oxidation Studies

Cited by 144 publications

References 8 publications

Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation: Effect of Pretreatment and Oxidation State on the Activity for Methanol Decomposition and Oxidation

Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation: Effect of Pretreatment and Oxidation State on the Activity for Methanol Decomposition and Oxidation

Molecular structures of supported metal oxide catalysts under different environments

Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

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