Solving the structure of nanoparticles by multiple-scattering EXAFS analysis.

The particle size effect on the coordination number in nanoparticles is much stronger for more distant coordination shells than for the first nearest neighbor shell. We show, using the EXAFS analysis of carbon-supported Pt and Pt-Ru nanoparticles, that it is possible to analyze the structure of monoand heteroatomie particles through the 4 ~ shell by taking into account multiple scatterings, and by using multiple edge refinement in the case of Pt-Ru alloy. Combined with the transmission electron microscopy and electron diffraction results, our procedure enabled us to obtain the particle shape and size in both types of the nanoelusters, and non-statistical distribution of Pt and Ru atoms in the alloy.