Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages
We present an experimental study of the initial dissociative sticking probability of H on the Pd–Cu(111) surface alloy at Pd coverages between 1–10%. The measurements have been performed using a supersonic molecular beam with an incident energy range = 75–163 meV. In agreement with a recent STM stu...
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Published in | Zeitschrift für physikalische Chemie (Neue Folge) Vol. 227; no. 11; pp. 1491 - 1500 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
De Gruyter
2013
|
Subjects | |
Online Access | Get full text |
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Summary: | We present an experimental study of the initial dissociative sticking
probability of H
on the Pd–Cu(111) surface alloy at Pd
coverages between 1–10%. The measurements have been performed
using a supersonic molecular beam with an incident energy range
= 75–163 meV. In agreement with a recent STM study, our results
confirm that small amounts of Pd atoms significantly increase the
reactivity of the inert Cu(111) surface, although the measured initial
sticking probability values were found to be much lower than the ones
estimated from the STM work. For a Pd coverage of 1% and
∼ 0.10 eV, the H
initial sticking probability was found to
be 2 × 10
, increasing to 4 × 10
for a Pd
coverage of 10%. This agrees well with a recent molecular dynamics
study, in which the initial sticking probability was estimated in 7 × 10
for a Pd coverage of 11% and
∼ 0.15–0.20 eV. Essentially the same values were measured in the whole
incident energy range investigated. Therefore, our results support the
main conclusion of the molecular dynamics calculations about the
mechanism leading to the increase of reactivity of the Pd–Cu(111)
surface alloy, which combines a lower activation energy barrier for
dissociation of ∼ 0.25 eV on top of substitutional Pd atoms with
spillover onto the Cu(111) surface. |
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ISSN: | 0942-9352 2196-7156 |
DOI: | 10.1524/zpch.2013.0392 |