Methane activation on Fe4 cluster: A density functional theory study

Sun, Qiang; Li, Zhen; Wang, Meng; Du, Aijun; Smith, Sean C.

doi:10.1016/j.cplett.2012.08.057

Cited by 18 publications

(7 citation statements)

References 32 publications

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“…Collision induced vibrational activation of methane is responsible for lowering the free energy barrier for the dissociation of the first C-H bond and is absent in subsequent dehydrogenation steps. However, computational investigation of methane activation on Fe 4 cluster 78 showed the cleavage of the second C-H bond is more difficult than the first and is in agreement with our observation.…”

Section: Reactive Trajectories and Free Energy Barrierssupporting

confidence: 91%

First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

Varghese

Mushrif

2015

The Journal of Chemical Physics

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Small metal clusters exhibit unique size and morphology dependent catalytic activity. The search for alternate minimum energy pathways and catalysts to transform methane to more useful chemicals and carbon nanomaterials led us to investigate collision induced dissociation of methane on small Cu clusters. We report here for the first time, the free energy barriers for the collision induced activation, dissociation, and coupling of methane on small Cu clusters (Cun where n = 2-12) using ab initio molecular dynamics and metadynamics simulations. The collision induced activation of the stretching and bending vibrations of methane significantly reduces the free energy barrier for its dissociation. Increase in the cluster size reduces the barrier for dissociation of methane due to the corresponding increase in delocalisation of electron density within the cluster, as demonstrated using the electron localisation function topology analysis. This enables higher probability of favourable alignment of the C-H stretching vibration of methane towards regions of high electron density within the cluster and makes higher number of sites available for the chemisorption of CH3 and H upon dissociation. These characteristics contribute in lowering the barrier for dissociation of methane. Distortion and reorganisation of cluster geometry due to high temperature collision dynamics disturb electron delocalisation within them and increase the barrier for dissociation. Coupling reactions of CHx (x = 1-3) species and recombination of H with CHx have free energy barriers significantly lower than complete dehydrogenation of methane to carbon. Thus, competition favours the former reactions at high hydrogen saturation on the clusters.

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Section: Reactive Trajectories and Free Energy Barrierssupporting

confidence: 91%

First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

Varghese

Mushrif

2015

The Journal of Chemical Physics

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“…Based on the optimized structures at the DFT-D level, we have calculated the wave functions at the B3LYP/6-31+G(d) level of theory, then the AIM theory is used. This approach has been used to successfully determine intermolecular interactions for a range of systems. ,, In the AIM analyses, existence of an interaction is indicated by the presence of a bond critical point (BCP) and the strength of the bond is estimated from the magnitude of the electron density (ρ bcp ) at the BCP. Similarly, ring or cage structures are characterized by the existence of a ring critical point (RCP) or cage critical point (CCP).…”

Section: Methodsmentioning

confidence: 99%

Carbon Dioxide Capture and Gas Separation on B₈₀Fullerene

Sun¹,

Wang

et al. 2014

J. Phys. Chem. C

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Exploring advanced materials for efficient capture and separation of CO2 is important for CO2 reduction and fuel purification. In this study, we have carried out first-principles density functional theory calculations to investigate CO2, N2, CH4, and H2 adsorption on the amphoteric regioselective B80 fullerene. Based on our calculations, we find that CO2 molecules form strong interactions with the basic sites of the B80 by Lewis acid–base interactions, while there are only weak bindings between the other three gases (N2, CH4, and H2) and the B80 adsorbent. The study also provides insight into the reaction mechanism of capture and separation of CO2 using the electron deficient B80 fullerene.

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“…Based on the optimized structures at the DFT-D level, we calculate the wavefunctions at the B3LYP/6-31G(d) level of theory, 21 we then use AIM theory, which has been used to successfully determine intermolecular interactions of different systems. 27,30,31 In the AIM analyses, 32 the existence of an interaction is indicated by the presence of a bond critical point (BCP), and the strength of the bond can be estimated from the magnitude of the electron density (ρ bcp ) at the BCP. Similarly, the ring or cage structures are characterized by the existence of a ring critical point (RCP) or cage critical point (CCP).…”

Section: Methodsmentioning

confidence: 99%