H2 dissociative adsorption on Mg, Ti, Ni, Pd and La Surfaces

Nobuhara, Katsuya; Kasai, Hideaki; Diño, Wilson Agerico; Nakanishi, Hiroshi

doi:10.1016/j.susc.2004.06.003

Cited by 86 publications

(50 citation statements)

References 11 publications

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“…Interestingly, the activation barriers for H 2 dissociation over the Ni/Ti-doped Mg surface are similar to the values found on the corresponding pure Ni/Ti surfaces [55,56,58].…”

Section: Discussionsupporting

confidence: 77%

“…The small barrier for hydrogen dissociation on Ni(111) is also confirmed by experiments [57]). Analogously, the behaviour of H 2 dissociation over the Ti-doped Mg surface appears to be similar to that obtained on the pure Ti(111) surface: the null activation barrier we find with a smaller 4x4x1 grid compares with theoretical results found over a Ti (0001) surface with an analogous grid [55,58]. In other words, this seems to suggest that the value of the activation barrier for hydrogen dissociation over a transition-metal doped Mg surface is similar to the activation barrier for H 2 dissociation over the corresponding pure transition-metal surface.…”

Section: H2 Dissociation and Diffusion On A Ni-doped Mg Surfacesupporting

confidence: 83%

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Hydrogen dissociation and diffusion on Ni- and Ti-doped Mg(0001) surfaces

Pozzo

Alfè

Amieiro

et al. 2008

The Journal of Chemical Physics

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It is well known, both theoretically and experimentally, that alloying MgH2 with transition elements can significantly improve the thermodynamic and kinetic properties for H2 desorption, as well as the H2 intake by Mg bulk. Here we present a density functional theory investigation of hydrogen dissociation and surface diffusion over Ni-doped surface, and compare the findings to previously investigated Ti-doped Mg(0001) and pure Mg(0001) surfaces. Our results show that the energy barrier for hydrogen dissociation on the pure Mg(0001) surface is high, while it is small/null when Ni/Ti are added to the surface as dopants. We find that the binding energy of the two H atoms near the dissociation site is high on Ti, effectively impeding diffusion away from the Ti site. By contrast, we find that on Ni the energy barrier for diffusion is much reduced. Therefore, although both Ti and Ni promote H2 dissociation, only Ni appears to be a good catalyst for Mg hydrogenation, allowing diffusion away from the catalytic sites. Experimental results corroborate these theoretical findings, i.e. faster hydrogenation of the Ni doped Mg sample as opposed to the reference Mg or Ti doped Mg.

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“…Interestingly, the activation barriers for H 2 dissociation over the Ni/Ti-doped Mg surface are similar to the values found on the corresponding pure Ni/Ti surfaces [55,56,58].…”

Section: Discussionsupporting

confidence: 77%

Section: H2 Dissociation and Diffusion On A Ni-doped Mg Surfacesupporting

confidence: 83%

Hydrogen dissociation and diffusion on Ni- and Ti-doped Mg(0001) surfaces

Pozzo

Alfè

Amieiro

et al. 2008

The Journal of Chemical Physics

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“…1). By symmetry, hbf(2) (tbt (2)) is equivalent to hbf(3) (tbt (3)), hence, the use of hbf(2/3) (tbt(2/3)) to represent both. The same is applied whenever two configurations are equivalent by symmetry.…”

Section: Methodsmentioning

confidence: 99%

Potential energy surfaces for H₂ dissociative adsorption on Pt(111) surface—effects of vacancies

Arboleda

Kasai

2008

Surface & Interface Analysis

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In this study, we determine the effects of having vacancies on the Pt(111) surface to the dissociative adsorption behavior of H 2 on Pt(111). We study the potential energy behaviors along the reaction paths based on the potential energy surfaces (PESs) we calculated that are relevant to these systems. Partial results of our current calculations, based on the density functional theory, reveal that vacancies on the substrate can significantly lower the barrier for the dissociative adsorption of H 2 on the Pt(111) surface. We attribute this behavior to the increased reactivity of the surface owing to the vacant sites. Of the substrate atoms, we find that those on the surface mainly influence the behavior of H 2 adsorption on Pt(111).

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“…Moreover, the results suggest that the presence of Ti decreases the activity of Pt. This is quite interesting since it is known that pure Ti substrate also shows negligible barrier for H 2 dissociation 16,17) and common intuition would predict the compound to behave near or intermediate to that of the metal components.…”

Section: Resultsmentioning

confidence: 94%

Density Functional Study on the Interaction of Hydrogen with Pt3Ti(111)

et al. 2006

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We investigate the catalytic property of the intermetallic compound Pt 3 Ti by studying the interaction of its (111) surface with hydrogen. Based on density functional theory, we obtain the 2-D PES to estimate the barrier for H 2 dissociation, and the binding energy of H atom at diŠerent sites of the substrate. The observed energetics can be explained in terms of the role played by the Ti atoms in the compound. Our results show that the Ti atoms function as inactive components that dilute the concentration of the active Pt components thus making the compound less active than Pt towards hydrogen.

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H2 dissociative adsorption on Mg, Ti, Ni, Pd and La Surfaces

Cited by 86 publications

References 11 publications

Hydrogen dissociation and diffusion on Ni- and Ti-doped Mg(0001) surfaces

Hydrogen dissociation and diffusion on Ni- and Ti-doped Mg(0001) surfaces

Potential energy surfaces for H₂ dissociative adsorption on Pt(111) surface—effects of vacancies

Density Functional Study on the Interaction of Hydrogen with Pt3Ti(111)

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H2 dissociative adsorption on Mg, Ti, Ni, Pd and La Surfaces

Cited by 86 publications

References 11 publications

Hydrogen dissociation and diffusion on Ni- and Ti-doped Mg(0001) surfaces

Hydrogen dissociation and diffusion on Ni- and Ti-doped Mg(0001) surfaces

Potential energy surfaces for H2 dissociative adsorption on Pt(111) surface—effects of vacancies

Density Functional Study on the Interaction of Hydrogen with Pt3Ti(111)

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Product

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Potential energy surfaces for H₂ dissociative adsorption on Pt(111) surface—effects of vacancies