XPS, ISS and TDS study of bimetallic interaction between Pd and Al: CO interaction with supported Pd/alumina catalysts

The metal–substrate interaction (MSI) represents an important effect determining the properties of supported heterogeneous catalysts. We investigated the MSI effects by X-ray photoelectron spectroscopy, ion scattering spectroscopy and thermal desorption spectroscopy in the case of Pd films vapor deposited on non-stoichiometric aluminum oxide substrates. We compared the obtained results with these of bulk Pd and Pd/Al reference alloy. The observed MSI is explained by the formation of an intermetallic interface exhibiting a strong bimetallic transition-metal (Pd)/s, p-metal (Al) interaction. The fundamental studies of Pd/Al bimetallic alloys are of an importance due to the role that they play in the modification of chemisorption and catalytic properties of real Pd/Al-oxide systems as well as in the realization of novel Pd-alloy catalysts. The reported behavior represents a new way in explanation of former unexpected CO adsorption properties of alumina supported Pd particles.