SUPPORT EFFECTS ON ELECTRONIC-STRUCTURE OF PLATINUM CLUSTERS IN Y-ZEOLITE

The electronic structure of platinum clusters of identical size and structure supported in Y zeolites with different acidities was probed by chemisorption, Fourier transform infrared spectroscopy, and X-ray absorption near-edge spectroscopy (XANES). The results indicate increase in ionization potential of Pt as the acidity of zeolites is increased. The XANES data show that the adsorption of hydrogen on the clusters increases the area under the white line at the Pt L(III) absorption edge, indicating the appearance of unoccupied antibonding states above the Fermi level.