Comparison of Pd/(Bulk SiC) Catalysts Prepared by Atomic Beam Deposition and Plasma Sputtering Deposition: Characterization and Catalytic Properties

Abstract

Pd on SiC catalysts have been prepared using two different physical processes: atomic beam deposition (ABD) and plasma sputtering deposition (PSD). Whatever the method, Pd deposition (ranging between 0.3 and about 12 monolayer equivalent) yields thin metal adlayers. However, the catalysts prepared by ABD exhibit a 2D-like growth, with a strong metal support interaction which remains even for the highest Pd contents investigated. At lower Pd content the presence of adatoms and/or small nuclei in strong interaction with the 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 have the typical properties of bulk palladium. While the ABD catalysts exhibit good activity toward the 1,3-butadiene hydrogenation reaction, whatever the Pd content, PSD catalysts with low Pd content were quite inactive and/or strongly deactivated. However, at higher Pd content the PSD technique produces rather good catalysts.