Oxidation of CO and NO on Composition-Selected Cerium Oxide Cluster Cations

Hirabayashi, Shinichi; Ichihashi, Masahiko

doi:10.1021/jp406339z

Cited by 37 publications

(57 citation statements)

References 39 publications

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“…The major difference between the two studies was the experimental conditions. The CID study was performed under single-collision conditions (∼10 −4 Torr, 34 namely, 10 12 −10 13 molecules cm −3 ), while in the present study, cluster ions collided with NO and He gases much more frequently in the reaction gas cell, which was a multiple-collision environment (10 17 −10 18 molecules cm −3 ). When the cluster ion formed a complex with a reactant molecule, the clusterreactant complex gained energy equivalent to the collision energy and binding energy.…”

Section: Comparison With Collision-induced Dissociationmentioning

confidence: 87%

“…Density functional theory (DFT) calculations suggested that there were two intermediates in the reaction pathway of NO oxidation. 34 One of these intermediates could be described as an NO moiety bound to Ce n O 2n + , while the other was an NO 2 bound to Ce n O 2n−1 + . The two intermediates will hereafter be denoted as Ce n O 2n + NO and Ce n O 2n−1 + NO 2 .…”

Section: Reactivity With Nomentioning

confidence: 99%

“…34 In the present study, the reaction cross sections of NO adsorption (reaction 1) were calculated from rate constants (Figure 2b) using…”

Section: Comparison With Collision-induced Dissociationmentioning

confidence: 99%

“…The redox activity of cerium oxide clusters for the oxidation of CO has been reported. 27,28,32,34 Figure 8 with "NO" replaced with "CO" and "NO 2 " replaced with "CO 2 ". It remains unclear why NO oxidation ceased at the intermediate complex at room temperature, while CO oxidation reached completion without thermal excitation.…”

Section: Comparison With Collision-induced Dissociationmentioning

confidence: 99%

“…34 In the present work, the oxidation of NO by cationic cerium oxide clusters was examined under the multiple-collision condition to determine detailed kinetic information. Interestingly, the reaction progressed differently than in the previous CID study.…”

Section: Introductionmentioning

confidence: 99%

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Oxidation of Nitric Oxide on Gas-Phase Cerium Oxide Clusters via Reactant Adsorption and Product Desorption Processes

2015

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The reactivity of cerium oxide cluster cations, CenO2n+x(+) (n = 2-9, x = -1 to +2), with NO was investigated using gas-phase temperature-programmed desorption (TPD) combined with mass spectrometry. Target clusters were prepared in the gas phase via the laser ablation of a cerium oxide rod in the presence of oxygen, which was diluted using helium as a carrier gas. NO adsorbed onto stoichiometric and oxygen-rich clusters of CenO2n+x(+) (x = 0-2), forming CenO2n+x(NO)(+) (x = 0-2) species. Gas-phase TPD was measured for the NO-adsorbed clusters, revealing that CenO2n(NO)(+) released NO2 at 600-900 K, forming CenO2n-1(+). Therefore, the overall reaction was the oxidation of NO by the CenO2n(+) clusters, which was explained in terms of a Langmuir-Hinshelwood type reaction. An activation barrier existed between the initial complex (CenO2n(NO)(+)) and the final oxidation products (CenO2n-1(+) + NO2). To determine the nature of the intermediates and the activation barrier, TPD was also performed on CenO2n-1(NO2)(+), which had been prepared through the adsorption of NO2 on CenO2n-1(+) for comparison. The activation barrier was associated with the release of NO2 from the intermediate complex (CenO2n-1(+)-NO2 → CenO2n-1(+) + NO2) rather than the structural rearrangement that formed NO2 in the other intermediate complex (CenO2n(+)-NO → CenO2n-1(+)-NO2).

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Section: Comparison With Collision-induced Dissociationmentioning

confidence: 87%

Section: Reactivity With Nomentioning

confidence: 99%

“…34 In the present study, the reaction cross sections of NO adsorption (reaction 1) were calculated from rate constants (Figure 2b) using…”

Section: Comparison With Collision-induced Dissociationmentioning

confidence: 99%

Section: Comparison With Collision-induced Dissociationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Oxidation of Nitric Oxide on Gas-Phase Cerium Oxide Clusters via Reactant Adsorption and Product Desorption Processes

2015

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Ursachen der unterschiedlichen Reaktivität von [AlCeO_x]⁺ (x=2–4) gegenüber Methan in Abhängigkeit vom Sauerstoffgehalt

Zhou

Schlangen

et al. 2016

Angewandte Chemie

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Die thermischen Gasphasenreaktionen der geschlossenschaligen heteronuklearen Metalloxidcluster [AlCeO x ] + (x = 2-4) mit Methan wurden mittels FT-ICR-Massenspektrometrie und quantenchemischer Rechnungen untersucht. Während [AlCeO 2 ] + und [AlCeO 4 ] + unter thermischen Bedingungen gegenüber Methan inert sind, reagiert [AlCeO 3 ] + spontan unter Wasserstoffatomabstraktion. Unter Berücksichtigung mechanistischer Aspekte konnten die Ursachen dieser deutlich unterschiedlichen Eigenschaften der [AlCeO x ] + /CH 4 -Paare aufgedeckt werden;d ie elektronische Grundlage der beispiellosen, einfachen Wasserstoffatomabstraktion von Methan durchd en geschlossenschaligen Cluster [AlCeO 3 ] + wird diskutiert.Aluminiumund cerhaltige Metalloxide stehen wegen ihrer katalytischen Funktion in vielen großtechnischen Umwandlungsprozessen von Kohlenwasserstoffen nach wie vor im Fokus der chemischen Forschung. [1] Um Einblicke in diese Prozesse zu gewinnen, wurden zahlreiche Gasphasenuntersuchungen durchgeführt, mit denen die Reaktionsmechanismen auf strikt molekularer Ebene aufgeklärt werden konnten. [2] So kann in Modellstudien zur Methanaktivierung das aktive Zentrum eines Katalysators nachgebildet und damit die katalytische Umsetzung von Methan in der kondensierten Phase verbessert werden. Während eine Reihe von alumini-) n ]C + (n = 3-5) [10] und [Al 2 TaO 5 ] + , [11] zur thermischen Aktivierung von Methan in der Lage ist, sind nur zwei Arten von cerhaltigen Clustern, nämlich [(CeO 2 ) n ]C + (n = 2-4) [12] und [(CeO 2 ) m (V 2 O 5 ) n ] + (m = 1, 2, n = 1-5; m = 3, n = 1-4), [13] bekannt, die unter thermischen Bedingungen spontan mit Methan reagieren. Darüber hinaus gibt es unseres Wissens keine Studien zur thermischen Methanaktivierung durch heteronukleare Al/Ce-Cluster in der Gasphase;ind er konden-sierten Phase dagegen werden Al/Ce-haltige Katalysatoren fürdie Methanaktivierung bereits genutzt. [14] Hier berichten wir, dass das geschlossenschalige Oxid [AlCeO 3 ] + unter thermischen Bedingungen ein Wasserstoffatom von Methan abstrahieren kann;i mU nterschied dazu sind die beiden Kationen [AlCeO 2 ] + und [AlCeO 4 ] + gegenüber diesem Substrat inert. Darüber hinaus ist das Verhalten von [AlCeO 3 ] + auch deutlich verschieden von dem anderer geschlossenschaliger Spezies wie [OTiH] + , [15] [AuCH 2 ] + , [16] [AuC] + , [17] [OSiOH] + , [18] [XHfO] + (X = F, Cl, Br), [19] [TaO 2 ] + , [20] [TaO 3 ] + , [21] [Al 2 TaO 5 ] + , [11] [AuTi 3 O x ] À (x = 7, 8) [22] und [AuV 2 O 6 ] + . [23] Zwar kçnnen auch diese Ionen Methan unter thermischen Bedingungen aktivieren, zur einfachen Wasserstoffatomabstraktion unter Verlust eines Methylradikals sind sie jedoch nicht in der Lage.D ie Ursachen der unterschiedlichen Reaktivitäten von [AlCeO x ] + (x = 2-4) gegenüber Methan sowie die besonderen Eigenschaften von [AlCeO 3 ] + werden hier diskutiert. Setzt man massenselektierte und thermalisierte [AlCeO x ] + -Ionen (x = 2-4) der Gegenwart von CH 4 aus, reagiert nur [AlCeO 3 ] + unter Bildung von [AlCeO 3 H]C + [Abbildung 1a und Gl. (1) (t...

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On the Origin of the Remarkably Variable Reactivities of [AlCeO_x]⁺ (x=2–4) towards Methane as a Function of Oxygen Content

Zhou

Schlangen

et al. 2016

Angew Chem Int Ed

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The thermal gas-phase reactions of the closed-shell heteronuclear metal-oxide clusters [AlCeO ] (x=2-4) with methane have been explored by FT-ICR mass spectrometry and high-level quantum-chemical calculation. Whereas [AlCeO ] and [AlCeO ] are inert towards methane under ambient conditions, [AlCeO ] spontaneously abstracts one hydrogen atom from methane. Mechanistic aspects have been addressed to reveal the reasons for the rather distinct reactivities of the [AlCeO ] /CH couples, and the electronic origins of the unprecedented single hydrogen-atom abstraction from methane by closed-shell [AlCeO ] are discussed.

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Oxidation of CO and NO on Composition-Selected Cerium Oxide Cluster Cations

Cited by 37 publications

References 39 publications

Oxidation of Nitric Oxide on Gas-Phase Cerium Oxide Clusters via Reactant Adsorption and Product Desorption Processes

Oxidation of Nitric Oxide on Gas-Phase Cerium Oxide Clusters via Reactant Adsorption and Product Desorption Processes

Ursachen der unterschiedlichen Reaktivität von [AlCeO_x]⁺ (x=2–4) gegenüber Methan in Abhängigkeit vom Sauerstoffgehalt

On the Origin of the Remarkably Variable Reactivities of [AlCeO_x]⁺ (x=2–4) towards Methane as a Function of Oxygen Content

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Oxidation of CO and NO on Composition-Selected Cerium Oxide Cluster Cations

Cited by 37 publications

References 39 publications

Oxidation of Nitric Oxide on Gas-Phase Cerium Oxide Clusters via Reactant Adsorption and Product Desorption Processes

Oxidation of Nitric Oxide on Gas-Phase Cerium Oxide Clusters via Reactant Adsorption and Product Desorption Processes

Ursachen der unterschiedlichen Reaktivität von [AlCeOx]+ (x=2–4) gegenüber Methan in Abhängigkeit vom Sauerstoffgehalt

On the Origin of the Remarkably Variable Reactivities of [AlCeOx]+ (x=2–4) towards Methane as a Function of Oxygen Content

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Ursachen der unterschiedlichen Reaktivität von [AlCeO_x]⁺ (x=2–4) gegenüber Methan in Abhängigkeit vom Sauerstoffgehalt

On the Origin of the Remarkably Variable Reactivities of [AlCeO_x]⁺ (x=2–4) towards Methane as a Function of Oxygen Content