Segregation at a small scale: synthesis of core-shell bimetallic RuPt nanoparticles, characterization and solid state NMR studies

摘要

Core-shell small RuPt nanoparticles stabilized by a polymer (polyvinylpyrrolidone, PVP) have been prepared by co-decomposition of [Ru(COD)(COT)] [(l,5-cyclooctadiene)(l,3,5-cyclooctatriene) ruthenium] and [Pt(CH3)2(COD)] [dimethyl(l,5-cyclooctadiene)platinum(II)] organometallic complexes at room temperature. The control of the metal segregation is made possible by the difference in the decomposition temperature of the metal precursors, giving rise to a heterogeneous nucleation process. The structural composition of these nanoparticles has been determined by a combination of techniques (TEM, HREM, WAXS, EXAFS, STEM-HAADF, IR, NMR). In particular, after adsorption of ~(13)CO as a probe molecule, solid-state NMR investigation provided useful information on the chemical segregation in these nanoparticles.