Dissociative Hydrogen Adsorption on Close-Packed Cobalt Nanoparticle Surfaces

    Authors

    E. A. Lewis; D. Le; C. J. Murphy; A. D. Jewell; M. F. G. Mattera; M. L. Liriano; T. S. Rahman;E. C. H. Sykes

    Comments

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    Abbreviated Journal Title

    J. Phys. Chem. C

    Keywords

    DENSITY-FUNCTIONAL THEORY; AUGMENTED-WAVE METHOD; THIN-FILMS; CO; CHEMISORPTION; CU(111); GROWTH; CO(0001); NI(111); ISLANDS; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, ; Multidisciplinary

    Abstract

    The dissociative adsorption of hydrogen on cobalt is central to a number of catalytic reactions, yet to date there are relatively few studies examining this important process. Here we utilize Co nanoparticles grown on Cu(111), instead of the traditional planar Co single crystals, to study a more catalytically relevant form of Co. We present scanning tunneling microscopy images of different phases of H on the close-packed Co nanoparticle surfaces with a range of densities. Our data reveal a so-far unreported high coverage phase of H with a (1 x 1) structure and elucidate the importance of spillover from step edges in H adsorption. We also illustrate that, in contrast to the low density phases, the H-(1 x 1) structure can only be formed at an intermediate temperature, indicating that compression to this higher-density phase is activated. Density functional theory calculations yield energies for each of the H overlayer structures, as well as their preferred geometries. This work is the first to report on higher coverage ( > 0.75 ML) phases of H on Co, which are undoubtedly important in catalytic systems at elevated pressure. Finally, through the use of epitaxial Co nanoparticle growth on Cu(111), we illustrate the importance of step edges in H-2 activation and the formation of dense H phases.

    Journal Title

    Journal of Physical Chemistry C

    Volume

    116

    Issue/Number

    49

    Publication Date

    1-1-2012

    Document Type

    Article

    Language

    English

    First Page

    25868

    Last Page

    25873

    WOS Identifier

    WOS:000312176100027

    ISSN

    1932-7447

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