Silicon Modified Pd Catalysts: XPS and Hydrogenation of Cyclohexene

Pd-black, modified with Si by decomposing Et₃SiH at 250 °C, was examined by XPS and cyclohexene hydrogenation. Si coats the surface and diffuses into Pd particles until hydrogenation activity ceases. Oxidation restores hydrogenation activity by converting surface Si to SiO₂, which is either permeable to H₂ or exists as islands on the Pd.