| Issue |
J. Phys. IV France
Volume 7, Number C2, Avril 1997
Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure
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| Page(s) | C2-863 - C2-865 | |
| DOI | https://doi.org/10.1051/jp4:1997260 | |
J. Phys. IV France 7 (1997) C2-863-C2-865
DOI: 10.1051/jp4:1997260
Reversible Deformation of SiO2-Supported PtAu6 Cluster Induced by the CO Adsorption by In Situ EXAFS
K. Asakura1, Y. Yuan2 and Y. Iwasawa21 Research Center for Spectrochemistry, Faculty of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan
2 Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan
Abstract
Structure and behavior of [(PPh3)Pt(Au(PPh3))6](1) supported on SiO2 surface have been studied by in-situ EXAFS. The structure of the cluster 1 is maintained after deposition on SiO2 at room temperature. Upon adsorption of CO little change in coordination number for Pt-Au is found in Pt L3-edge EXAFS though the coordination number of Au-Au slightly increases in Au L3-edge EXAFS and the peak corresponding to Pt(-Au-)P remarkably increases in the Fourier transformation of Pt L3-edge EXAFS. We have interpreted the increase in the intensity of the peak corresponding to Pt(-Au-)P by the multiple scattering effect owing to the change of Pt-Au-P angle. The original EXAFS oscillations are regenerated for both Pt and Au L3-edges after the evacuation for 2 h at 353 K accompanied by the desorption of CO. From these EXAFS results and the analogy to the PtAu6 chemistry in solution, the PtAu6 framework transfoms its structure to a more compact one by CO adsorption with the change in the angle of Pt-Au-P. Unlike the PtAu6 cluster in solution, CO reversibly desorbs from the cluster without collapse of the PtAu6 framework.
© EDP Sciences 1997