Parahydrogen Conversion on Tungsten

Eley, D. D.; Rideal, Eric K.

doi:10.1038/146401d0

Cited by 173 publications

(106 citation statements)

References 2 publications

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“…More generally, the many elementary processes that take place in the (H+H 2 )/W interface are highly relevant, and remain a hot topic after almost a century of intense research. 4 A tungsten surface exposed to a gas of atomic and/or molecular hydrogen will be quickly covered by H atoms. Then, an impinging H atom coming from the gas phase (named in the following projectile) can react with a second H atom adsorbed on the surface (named target) to form a desorbing H 2 molecule.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of H2 Eley-Rideal abstraction from W(110): Sensitivity to the representation of the molecule-surface potential

Pétuya

Larrégaray

Busnengo

et al. 2014

The Journal of Chemical Physics

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Dynamics of the Eley-Rideal (ER) abstraction of H 2 from W(110) is analyzed by means of quasiclassical trajectory calculations. Simulations are based on two different molecule-surface potential energy surfaces (PES) constructed from Density Functional Theory results. One PES is obtained by fitting, using a Flexible Periodic London-Eyring-Polanyi-Sato (FPLEPS) functional form, and the other by interpolation through the corrugation reducing procedure (CRP). Then, the present study allows us to elucidate the ER dynamics sensitivity on the PES representation. Despite some sizable discrepancies between both H+H/W(110) PESs, the obtained projectile-energy dependence of the total ER cross sections are qualitatively very similar ensuring that the main physical ingredients are captured in both PES models. The obtained distributions of the final energy among the different molecular degrees of freedom barely depend on the PES model, being most likely determined by the reaction exothermicity. Therefore, a reasonably good agreement with the measured final vibrational state distribution is observed in spite of the pressure and material gaps between theoretical and experimental conditions.

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Section: Introductionmentioning

confidence: 99%

Dynamics of H2 Eley-Rideal abstraction from W(110): Sensitivity to the representation of the molecule-surface potential

Pétuya

Larrégaray

Busnengo

et al. 2014

The Journal of Chemical Physics

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“…Up to now, various reaction mechanisms for CO oxidation have been proposed, among which the three most popular mechanisms are the Langmuir-Hinshelwood mechanism 8,11,12 , the Eley-Rideal mechanism 8,13 and the Mars-van Krevelen mechanism 14 . Although these mechanisms have been proposed to investigate the catalytic reaction processes, atomic-level insights into the underlying mechanism of catalysis are less explored.…”

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confidence: 99%

Pits confined in ultrathin cerium(IV) oxide for studying catalytic centers in carbon monoxide oxidation

et al. 2013

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Finding ideal material models for studying the role of catalytic active sites remains a great challenge. Here we propose pits confined in an atomically thin sheet as a platform to evaluate carbon monoxide catalytic oxidation at various sites. The artificial three-atomic-layer thin cerium(IV) oxide sheet with approximately 20% pits occupancy possesses abundant pit-surrounding cerium sites having average coordination numbers of 4.6 as revealed by X-ray absorption spectroscopy. Density-functional calculations disclose that the four-and five-fold coordinated pit-surrounding cerium sites assume their respective role in carbon monoxide adsorption and oxygen activation, which lowers the activation barrier and avoids catalytic poisoning. Moreover, the presence of coordination-unsaturated cerium sites increases the carrier density and facilitates carbon monoxide diffusion along the two-dimensional conducting channels of surface pits. The atomically thin sheet with surface-confined pits exhibits lower apparent activation energy than the bulk material (61.7 versus 122.9 kJ mol À 1 ), leading to reduced conversion temperature and enhanced carbon monoxide catalytic ability.

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“…23,24 On the sub-picosecond time scale, recombinations proceed via Eley-Rideal (ER) or Hot-Atom (HA) abstractions. The former mechanism involves direct collision between a scattering atom (projectile) and an adsorbed species (target), 30 while the latter is governed by hyperthermal diffusion of the projectile onto the surface prior to abstraction. 31 The influence of the crystal face has been recently scrutinized theoretically for the Eley-Rideal (ER) recombination a) pascal.larregaray@u-bordeaux.fr of hydrogen and nitrogen on the W(100) and W(110) surfaces, [32][33][34][35][36] accounting for dissipation to surface phonons and electrons.…”

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confidence: 99%

Communication: Hot-atom abstraction dynamics of hydrogen from tungsten surfaces: The role of surface structure

Galparsoro

Busnengo

Juaristi

et al. 2017

The Journal of Chemical Physics

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Adiabatic and non-adiabatic quasiclassical molecular dynamics simulations are performed to investigate the role of the crystal face on hot-atom abstraction of H adsorbates by H scattering from covered W(100) and W(110). On both cases, hyperthermal diffusion is strongly affected by the energy dissipated into electron-hole pair excitations. As a result, the hot-atom abstraction is highly reduced in favor of adsorption at low incidence energy and low coverages, i.e., when the mean free path of the hyperthermal H is typically larger. Qualitatively, this reduction is rather similar on both surfaces, despite at such initial conditions, the abstraction process involves more subsurface penetration on W(100) than on W(110).

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Parahydrogen Conversion on Tungsten

Cited by 173 publications

References 2 publications

Dynamics of H2 Eley-Rideal abstraction from W(110): Sensitivity to the representation of the molecule-surface potential

Dynamics of H2 Eley-Rideal abstraction from W(110): Sensitivity to the representation of the molecule-surface potential

Pits confined in ultrathin cerium(IV) oxide for studying catalytic centers in carbon monoxide oxidation

Communication: Hot-atom abstraction dynamics of hydrogen from tungsten surfaces: The role of surface structure

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