Catalytic evidence of the core/shell structure of bimetallic Pd/Rh colloids

The co-reduction of [Rh(C2H4)(2)Cl](2) and [Pd(eta(3)-C3H5)Cl](2) with vanadocene [Cp2V] in THF, and in presence of poly(vinylpyrrolidone) (PVP), gives bimetallic PVP-protected Rh/Pd colloids. HREM and WAXS experiments show a narrow size distribution centered near 2 nm, indicating the existence of bimetallic particles rather than physical mixtures of monometallic ones. CO chemisorption, followed by IR in CH2Cl2, as well as catalytic hydrogenation of quinoline and phenylacetylene, followed by GC in CH2Cl2 or CH2Cl2/H2O, confirm the presence of core/shell-structured bimetallic colloids, with Pd atoms surrounded by Rh atoms.