| A series of Pt-Co planar model catalysts with various Pt/Co ratios have been characterized and tested in crotonaldehyde hydrogenation. Bimetallic catalysts were characterized by RBS, AFM and XPS. The formation of the active phase has been investigated by in situ soft X-ray absorption spectroscopy. The NEXAFS measurements performed under 1-2 mbar of H2 show a modification of the electronic structure of Co as the Pt/(Pt+Co) ratio increases indicating that both Pt and Co are in close interaction. This modification of the electronic structure may be due to either (1) electron transfer or (2) a change in the d-band structure. In order to elucidate this matter, which is crucial to understand structure-catalytic activity relationship, we plan to perform a series of calculations on Pt-Co particles with a radius ranging from 3 Å to 10 Å. These calculations have not been reported in the literature, up to our knowledge. |
