| AVS 61st International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | Stefan Duerrbeck, University of Innsbruck, Austria |
| Authors: | N. Oberkalmsteiner, University of Innsbruck, Austria M. Cordin, University of Innsbruck, Austria S. Duerrbeck, University of Innsbruck, Austria E. Bertel, University of Innsbruck, Austria J. Redinger, Vienna University of Technology, Austria C. Franchini, University of Vienna, Austria |
| Correspondent: | Click to Email |
Iodine-surface interactions are of considerable interest in sustainable-energy research. For instance, Iodine is used as redox shuttle in dye-sensitized solar cells and serves as a promoter in photocatalytic water splitting. In most of these applications, Pt is involved either as an electrode or as co-catalyst or both. As part of a general study of Pt-halogen interaction we discuss here the adsorption of Iodine on Pt(110) at a coverage (Θ) of 0.5 monolayers (ML). The I/Pt(110) adsorbate system was investigated by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED) and by density functional theory (DFT) calculations using both, the LDA and the GGA approximation. Remarkably, three different phases involving occupation of two different binding sites were found to coexist at Θ = 0.5 ML. While the observed phases are similar to the ones reported for Br on Pt(110)1-2, the preferred binding sites are different. The structure of defects in the adsorbate layer as well as the dynamics at the transition between the nearly degenerate phases is not the same as the one in a Br layer indicating a shifted balance of adsorbate-substrate binding and inter-adsorbate repulsion. The c(2×2)->(3×2) phase transition shows evidence for a long-range interaction. The latter phase also involves a surprisingly strong buckling in the Pt surface amounting to 15% of the interlayer distance. While the DFT calculations reflect the energetic details of the c(2×2) phase with stunning precision, they only partially reproduce the experimental results from the (3×2) phase. Comparison with literature data shows that the iodine adlayer is almost floating on Au(110) and uniaxially compressible on Pd(110), while on Pt(110) Iodine adsorption is tied to specific adsorption sites, precluding the formation of compression structures.
1 E. Doná, T. Loerting, S. Penner, et al., Physical Review Letters 98, 186101 (2007).
2 M. Cordin, B. A. J. Lechner, S. Duerrbeck, et al., Sci. Rep. 4 (2014).