Dissociation dynamics of ethylene molecules on a Ni cluster using<i>ab initio</i>molecular dynamics simulations

Shimamura, Kohei; Shibuta, Yasushi; Ohmura, Satoshi; Arifin, Rizal; Shimojo, Fuyuki

doi:10.1088/0953-8984/28/14/145001

Cited by 9 publications

(6 citation statements)

References 73 publications

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“…In this way, NH 3 fragments can become NH 3 molecules (or can be desorbed) with the support of the N atoms such as N2. Similar catalytic reactions have been observed in previous studies using the AIMD simulations, 53,54 where H 2 production processes on Ni cluster was discussed. It was clarified that C atoms existing on the Ni cluster surface catalytically supported the desorption of H 2 molecules from the Ni cluster.…”

Section: Dissociative Production Mechanism Of An Nh 3 Moleculesupporting

confidence: 87%

Meteorite impacts on ancient oceans opened up multiple NH₃ production pathways

Shimamura

Shimojo

Nakano

et al. 2017

Phys. Chem. Chem. Phys.

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A recent series of shock experiments by Nakazawa et al. starting in 2005 (e.g. [Nakazawa et al., Earth Planet. Sci. Lett., 2005, 235, 356]) suggested that meteorite impacts on ancient oceans would have yielded a considerable amount of NH to the early Earth from atmospheric N and oceanic HO through reduction by meteoritic iron. To clarify the mechanisms, we imitated the impact events by performing multi-scale shock technique-based ab initio molecular dynamics in the framework of density functional theory in combination with multi-scale shock technique (MSST) simulations. Our previous simulations with impact energies close to that of the experiments revealed picosecond-order rapid NH production during shock compression [Shimamura et al., Sci. Rep., 2016, 6, 38952]. It was also shown that the reduction of N took place with an associative mechanism as seen in the catalysis of nitrogenase enzymes. In this study, we performed an MSST-AIMD simulation to investigate the production by meteorite impacts with higher energies, which are closer to the expected values on the early Earth. It was found that the amount of NH produced further increased. We also found that the increased NH production is due to the emergence of multiple reaction mechanisms at increased impact energies. We elucidated that the reduction of N was not only attributed to the associative mechanism but also to a dissociative mechanism as seen in the Haber-Bosch process and to a mechanism through a hydrazinium ion. The emergence of these multiple production mechanisms capable of providing a large amount of NH would support the suggestions from recent experiments much more strongly than was previously believed, i.e., shock-induced NH production played a key role in the origin of life on Earth.

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Section: Dissociative Production Mechanism Of An Nh 3 Moleculesupporting

confidence: 87%

Meteorite impacts on ancient oceans opened up multiple NH₃ production pathways

Shimamura

Shimojo

Nakano

et al. 2017

Phys. Chem. Chem. Phys.

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“…Although various experimental techniques, including Raman scattering, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, have widely been used to reveal the mechanism of metal dusting corrosions, it has so far not been fully understood. ,, In fact, the understanding of the microprocesses and the detailed mechanism of this reaction can be advanced through computer simulations. Up to now, many theoretical studies focused on the adsorption and decomposition of carbon-containing gases on metal surfaces or particles. − First principle simulations are accurate enough to identify carburization and metal dusting mechanisms. Nevertheless, this approach remains extremely computationally demanding, even with massively parallel high-performance computer systems, preventing its application to large-scale issues.…”

Section: Introductionmentioning

confidence: 99%

Early Events of the Carburization of Fe Nanoparticles in Ethylene Pyrolysis: Reactive Force Field Molecular Dynamics Simulations

2018

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The carburization of transition metals in hydrocarbon pyrolysis is a common corrosion phenomenon in the petrochemical industry. Nevertheless, early events of carburization mechanism remain still unclear. The present work reveals the details at earlier stages of the Fe nanoparticles carburization in ethylene (C2H4) pyrolysis with reactive ReaxFF force field molecular dynamics simulations. Our results show that the chemisorption and dissociation of C2H4 on Fe surfaces are crucial steps to the carburization corrosion. First of all, C2H4 molecules are chemically adsorbed on the surface of the Fe nanoparticle. Afterward, continuous dehydrogenation of C2H4 occurs by C–H bond break to form C2H x (x = 0–3). And finally, an amorphous C-rich carbide FeC3.39 is obtained. The carbide formation proceeds in four sequential and repetitive stages, including chemisorption and dehydrogenation of C2H4 on the surface of the Fe nanoparticle, diffusion and polymerization of C2H x to form short C chains on the surface and in the bulk of the particle, growth and branching of the short chains, and chain cross-linking to form longer and more branched chains. Our finding provides deep insight into the fundamental process of carburization corrosion of Fe nanoparticles in the hydrocarbon pyrolysis, as a common phenomenon observed in practice.

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“…Adsorption and reaction of hydrocarbons on transition metal surfaces are an interesting topic due to their relevance in heterogeneous catalysis and nanotechnology. Interaction between hydrocarbon and the metal substrate has effects on various processes like hydrogenation [1,2], dissociation [3], and polymerization [4]. Recently, copper is widely used as a catalyst to grow two-dimensional graphene sheets via chemical vapor deposition of methane, ethane, or other hydrocarbon precursors [7].…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of adsorption and dehydrogenation of C2H4 on Cu(410)

Sun

Zhang

et al. 2018

Chinese Journal of Chemical Physics

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Adsorption and dehydrogenation of ethylene on Cu(410) surface are investigated with firstprinciples calculations and micro-kinetics analysis. Ethylene dehydrogenation is found to start from the most stable π-bonded state instead of the previously proposed di-σ-bonded state. Our vibrational frequencies calculations verify the π-bonded adsorption at step sites at low coverage and low surface temperature and di-σ-bonded ethylene on C−C dimer (C 2 H 4-CC) is proposed to be the species contributing to the vibrational peaks experimentally observed at high coverage at 193 K. The presence of C 2 H 4-CC indicates that the dehydrogenation of ethylene on Cu(410) can proceed at temperature as low as 193 K.

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Dissociation dynamics of ethylene molecules on a Ni cluster usingab initiomolecular dynamics simulations

Cited by 9 publications

References 73 publications

Meteorite impacts on ancient oceans opened up multiple NH₃ production pathways

Meteorite impacts on ancient oceans opened up multiple NH₃ production pathways

Early Events of the Carburization of Fe Nanoparticles in Ethylene Pyrolysis: Reactive Force Field Molecular Dynamics Simulations

Theoretical study of adsorption and dehydrogenation of C2H4 on Cu(410)

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Dissociation dynamics of ethylene molecules on a Ni cluster usingab initiomolecular dynamics simulations

Cited by 9 publications

References 73 publications

Meteorite impacts on ancient oceans opened up multiple NH3 production pathways

Meteorite impacts on ancient oceans opened up multiple NH3 production pathways

Early Events of the Carburization of Fe Nanoparticles in Ethylene Pyrolysis: Reactive Force Field Molecular Dynamics Simulations

Theoretical study of adsorption and dehydrogenation of C2H4 on Cu(410)

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Meteorite impacts on ancient oceans opened up multiple NH₃ production pathways

Meteorite impacts on ancient oceans opened up multiple NH₃ production pathways