Adsorption and diffusion of hydrogen on Pd(211) and Pd(111): Results from first-principles electronic structure calculations

    Authors

    S. Hong;T. S. Rahman

    Comments

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    Abbreviated Journal Title

    Phys. Rev. B

    Keywords

    ORDER-DISORDER TRANSITIONS; SUBSURFACE OCCUPATION; MOLECULAR-DYNAMICS; QUANTUM DIFFUSION; SURFACE; PALLADIUM; METALS; TEMPERATURE; ABSORPTION; ENERGY; Physics, Condensed Matter

    Abstract

    We have carried out first-principles calculations of H adsorption on Pd(211) using density-functional theory with the generalized gradient approximation in the plane-wave basis to find out that the most preferred is the threefold hollow site on the terrace of Pd(211) with an adsorption energy of 0.52 eV: the hcp and fcc sites being almost energetically equally favorable. For subsurface H adsorption on Pd(211), the octahedral site with an adsorption energy of 0.19 eV is slightly more favorable than the tetrahedral site (0.18 eV). Our calculated activation energy barrier for H to diffuse from the preferred surface site to the subsurface one on Pd(211) is 0.33 eV, as compared with 0.41 eV on Pd(111). Thus, there is an enhancement of the probability of finding subsurface hydrogen in Pd(211). Additionally, we find the diffusion barriers for H on the terraces of Pd(211) to be 0.11 eV, while that along the step edge to be only 0.05 eV and that within the second layer (subsurface) to be 0.15 eV.

    Journal Title

    Physical Review B

    Volume

    75

    Issue/Number

    15

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    10

    WOS Identifier

    WOS:000246075300101

    ISSN

    1098-0121

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