Fabrication of palladium-copper nanoparticles with controllable size and chemical composition

Abstract

A series of PdxCu100−x (x = 20, 40, 60, 80) particles with the sizes of 7–9 nm were fabricated by a two-step polyol reduction process, which differentiated the nucleation and growth steps of the nanoparticles. The primary reduction of Pd2+ by ethylene glycol at 393 K formed appreciable amounts of Pd0 nuclei, while the subsequent reduction at 473 K fully reduced the Pd2+ and Cu2+ species with the aid of the initially formed Pd nuclei seeds. Meanwhile, the releasing oleylamine, previously coordinated with metal cations, acted as the capping agent to segregate the nanoparticles. Both parameters simultaneously controlled the assembly kinetics of the bimetallic nanoparticles and resulted in uniform sizes and designed chemical compositions. Among them, the Pd80Cu20 nanoparticles showed quite promising activity and selectivity for the hydrogenation of nitrobenzene under mild conditions.