Paper SS+NS-WeM2
Heats of Adsorption and Surface Reaction for CO and O2 on Pd Nanoparticles by Single Crystal Adsorption Microcalorimetry
Wednesday, October 30, 2013, 8:20 am, Room 201 A
| Session: |
Nanostructures: Reactivity & Catalysis |
| Presenter: |
S. Schauermann, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany |
| Authors: |
S. Schauermann, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
M. Peter, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
J.M. Flores-Camacho, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
J.-H. Fischer-Wolfarth, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
S. Adamovski, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
H.-J. Freund, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
|
| Correspondent: |
Click to Email |
Establishing the correlation between the energetics of adsorbate-surface interaction and the structural properties of a catalyst is an important fundamental issue and an essential prerequisite for understanding the realistic catalytic processes. We apply a newly developed microcalorimetry set up to determine the adsorption heats of carbon monoxide and oxygen on Pd nanoparticles supported on a well-define Fe3O4/Pt(111) film. We systematically vary the Pd cluster size in the range of ~ 100 to 5000 Pd atoms to address the energetics of CO and O interaction with the nanoparticles of different dimensions. Particularly, two major structural factors were identified that determine the CO and oxygen binding energy on Pd: the local configuration of the adsorption site, and the particle size. We show that the change of the binding site from a three-fold hollow site at Pd(111) to the edges of Pd nanoparticles results in a strong increase of the oxygen binding energy, while this effect is absent for CO adsorption, pointing to the adsorbate-specific nature of this factor. In contrast, the decreasing particle size was shown to result in strongly decreasing binding energies for both adsorbates. In case of oxygen, these both counteracting trends were found to give rise to a non-monotonous dependence of the oxygen adsorption energy on the particle size [1,2].[1] J.-H. Fischer-Wolfarth, J.A. Farmer, J.M. Flores-Camacho, A. Genest, I.V. Yudanov, N. Rösch, C.T. Campbell, S. Schauermann, H.-J. Freund, Phys. Rev. B, 81, 2010, 241416(R)
[2] M. Peter, J. M. Flores Camacho, S. Adamovski, L.K. Ono, K.-H. Dostert, C.P. O’Brien, B. Roldan Cuenya, S. Schauermann, H.-J. Freund, Angew. Chem. Int. Edit. DOI: 10.1002/anie.201209476