Reactions of platinum clusters Ptn<sup>±</sup>, n = 1–21, with CH<sub>4</sub>: to react or not to react

Adlhart, Christian; Uggerud, Einar

doi:10.1039/b604207d

Cited by 72 publications

(72 citation statements)

References 13 publications

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“…Gas‐phase studies of methane activation by metal atoms and clusters have provided insight into methane functionalization at the molecular level . In the case of platinum the reactivities of its cationic, neutral, and anionic atoms and clusters with methane have been widely investigated . For its atoms, in particular, both cationic and neutral platinum atoms have been shown to activate methane, yielding both dehydrogenation and C−H insertion products, whereas anionic platinum atoms were found in FT‐ICR mass spectrometric experiments to exhibit only negligible reactivity toward methane…”

Section: Figurementioning

confidence: 99%

Selective Activation of the C−H Bond in Methane by Single Platinum Atomic Anions

et al. 2019

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Mass spectrometric analysis of the anionic products of interaction between platinum atomic anions,P t À ,a nd methane,CH 4 and CD 4 ,inacollision cell shows the preferred generation of [PtCH 4 ] À and [PtCD 4 ] À complexes and al ow tendency toward dehydrogenation. [PtCH 4 ] À is shown to be H À Pt À CH 3 À by as ynergy between anion photoelectron spectroscopya nd quantum chemical calculations,i mplying the rupture of as ingle CÀHb ond. The calculated reaction pathway accounts for the observed selective activation of methane by Pt À .T his study presents the first example of methane activation by as ingle atomic anion.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under https://doi.

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Section: Figurementioning

confidence: 99%

Selective Activation of the C−H Bond in Methane by Single Platinum Atomic Anions

et al. 2019

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“…31 Among the smallest clusters, particular attention has been paid to Pt tetramers and methane dehydrogenation. 32,33 …”

Section: Introductionmentioning

confidence: 99%

Subnanometer-sized Pt/Sn alloy cluster catalysts for the dehydrogenation of linear alkanes

Hauser

Gomes

Bajdich

et al. 2013

Phys. Chem. Chem. Phys.

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The reaction pathways for the dehydrogenation of ethane, propane, and butane, over Pt are analyzed using density functional theory (DFT). Pt nanoparticles are represented by a tetrahedral Pt 4 cluster. The objectives of this work were to establish which step is rate limiting and which one controls the selectivity for forming alkenes as opposed to causing further dehydrogenation of adsorbed alkenes to produce precursors responsible for catalyst deactivation due to coking. Further objectives of this work are to identify the role of adsorbed hydrogen, derived from H 2 fed together with the alkane, on the reaction pathway, and the role of replacing one of the four Pt atoms by a Sn atom. A comparison of Gibbs free energies shows that in all cases the rate-determining step is cleavage of a C-H bond upon alkane adsorption. The selectivity to alkene formation versus precursors to coking is dictated by the relative magnitudes of the activation energies for alkene desorption and dehydrogenation of the adsorbed alkene. The presence of an adsorbed H atom on the cluster facilitates alkene desorption relative to dehydrogenation of the adsorbed alkene. Substitution of a Sn atom in the cluster to produce a Pt 3 Sn cluster leads to a downward shift of the potential energy surface for the reaction and causes an increase of the activity of the catalyst as suggested by recent experiments due to the lower net activation barrier for the rate limiting step. However, the introduction of Sn does not alter the relative activation barriers for gas-phase alkene formation versus loss of hydrogen from the adsorbed alkene, the process leading to the formation of coke precursors.

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“…The neutral, cationic, and anionic Pt atomic and cluster species Pt n (n = 1-24), [24] Pt n + (n = 1-21), [23,25] and Pt n À (n = 2- 5,7,11,12) [23,25] all can activate methane in the gas phase, for example: [26,27] Pt q þ CH 4 ! The neutral, cationic, and anionic Pt atomic and cluster species Pt n (n = 1-24), [24] Pt n + (n = 1-21), [23,25] and Pt n À (n = 2- 5,7,11,12) [23,25] all can activate methane in the gas phase, for example: [26,27] Pt q þ CH 4 !…”

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confidence: 99%

Thermal Methane Conversion to Formaldehyde Promoted by Single Platinum Atoms in PtAl₂O₄⁻ Cluster Anions

Zhao

Yuan

et al. 2014

Angewandte Chemie

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Identification and mechanistic study of thermal methane conversion mediated by gas-phase species is important for finding potentially useful routes for direct methane transformation under mild conditions. Negatively charged oxide species are usually inert with methane. This work reports an unexpected result that the bi-metallic oxide cluster anions PtAl 2 O 4 À can transform methane into a stable organic compound, formaldehyde, with high selectivity. The clusters are prepared by laser ablation and reacted with CH 4 in an ion trap reactor. The reaction is characterized by mass spectrometry and density functional theory calculations. It is found that platinum rather than oxygen activates CH 4 at the beginning of the reaction. The Al 2 O 4 À moiety serves as the support of Pt atom and plays important roles in the late stage of the reaction. A new mechanism for selective methane conversion is provided and new insights into the surface chemistry of single Pt atoms may be obtained from this study.

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Reactions of platinum clusters Ptn^±, n = 1–21, with CH₄: to react or not to react

Abstract: The relative reactivity of any given neutral platinum cluster falls in-between that of the corresponding anion and cation.

Cited by 72 publications

References 13 publications

Selective Activation of the C−H Bond in Methane by Single Platinum Atomic Anions

Selective Activation of the C−H Bond in Methane by Single Platinum Atomic Anions

Subnanometer-sized Pt/Sn alloy cluster catalysts for the dehydrogenation of linear alkanes

Thermal Methane Conversion to Formaldehyde Promoted by Single Platinum Atoms in PtAl₂O₄⁻ Cluster Anions

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Reactions of platinum clusters Ptn±, n = 1–21, with CH4: to react or not to react

Abstract: The relative reactivity of any given neutral platinum cluster falls in-between that of the corresponding anion and cation.

Cited by 72 publications

References 13 publications

Selective Activation of the C−H Bond in Methane by Single Platinum Atomic Anions

Selective Activation of the C−H Bond in Methane by Single Platinum Atomic Anions

Subnanometer-sized Pt/Sn alloy cluster catalysts for the dehydrogenation of linear alkanes

Thermal Methane Conversion to Formaldehyde Promoted by Single Platinum Atoms in PtAl2O4− Cluster Anions

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Product

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Reactions of platinum clusters Ptn^±, n = 1–21, with CH₄: to react or not to react

Thermal Methane Conversion to Formaldehyde Promoted by Single Platinum Atoms in PtAl₂O₄⁻ Cluster Anions