Comparison of Pd/(bulk SiC) catalysts prepared by atomic beam deposition and plasma sputtering deposition: Characterization and catalytic properties

Pd on SiC catalysts have been prepared using two different physical process es: atomic beam deposition (ABD) and plasma sputtering deposition (PSD). Wh atever the method, Pd deposition (ranging between 0.3 and about 12 monolaye r equivalent) yields thin metal adlayers. However, the catalysts prepared b y ABD exhibit a 2D-like growth, with a strong metal support interaction whi ch remains even for the highest Id contents investigated. At lower Pd conte nt the presence of adatoms and/or small nuclei in strong interaction with t he SiC support is evidenced for samples prepared by PSD; but increasing the Pd content of PSD samples yields a rapid growth of 3D Pd particles which h ave the typical properties of bulk palladium. While the ABD catalysts exhib it good activity toward the 1,3-butadiene hydrogenation reaction, whatever the Pd content, PSD catalysts with low Pd content were quite inactive and/o r strongly deactivated. However, at higher Pd content the PSD technique pro duces rather good catalysts. (C) 2000 Academic Press.