Fast synthesis of Ag–Pd@reduced graphene oxide bimetallic nanoparticles and their applications as carbon–carbon coupling catalysts

Abstract

Ultrafine Ag–Pd bimetallic nanoparticles homogeneously distributed on reduced graphene oxide (rGO) were prepared by redox reactions between Pd²⁺, Ag⁺ and GO. This method is simple, and the use of rGO as a support facilitated the separation and reuse of the Ag–Pd@rGO catalyst. The Ag–Pd@rGO bimetallic nanoparticles were characterized by ultraviolet-visible spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The microstructure of the Ag–Pd@rGO was investigated with scanning electron microscopy and transmission electron microscopy. The Ag–Pd@rGO catalyst exhibited high catalytic activities in the Suzuki-Miyaura carbon coupling reaction and the Sonogashira carbon coupling (SCC) reaction. These reactions used mild, efficient, ligand-free and heterogeneous conditions. Interestingly, the presence or absence of oxygen in the SCC catalytic system resulted in two different products, in which oxygen can be used as “switch” to control different products.