Hydrogen adsorption on palladium and palladium hydride at 1 bar

M. Johansson, E. Skúlason, G. Nielsen, S. Murphy, R. M. Nielsen, I. Chorkendorff*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

121 Citations (Scopus)


The dissociative sticking probability for H2 on Pd films supported on sputtered Highly Ordered Pyrolytic Graphite (HOPG) has been derived from measurements of the rate of the H-D exchange reaction at 1 bar. The sticking probability for H2, S, is higher on Pd hydride than on Pd (a factor of 1.4 at 140 °C), but the apparent desorption energy derived from S is the same on Pd and Pd hydride within the uncertainty of the experiment. Density Functional Theory (DFT) calculations for the (1 1 1) surfaces of Pd and Pd hydride show that, at a surface H coverage of a full mono layer, H binds less strongly to Pd hydride than to Pd. The activation barrier for desorption at a H coverage of one mono layer is slightly lower on Pd hydride, whereas the activation energy for adsorption is similar on Pd and Pd hydride. It is concluded that the higher sticking probability on Pd hydride is most likely caused by a slightly lower equilibrium coverage of H, which is a consequence of the lower heat of adsorption for H on Pd hydride.

Original languageEnglish
Pages (from-to)718-729
Number of pages12
JournalSurface Science
Issue number7-8
Publication statusPublished - 15 Apr 2010

Bibliographical note

Funding Information:
Center for Individual Nanoparticle Functionality (CINF) is sponsored by The Danish National Research Foundation .

Other keywords

  • Adsorption
  • DFT
  • Hydrogen
  • Palladium
  • Polycrystalline


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