Surfactant-Free Synthesis of Uniform Cu₃Pd Alloy Nanoparticles on Graphene for Enhanced Domino Sonogashira...

Highly dispersed bimetallic alloy nanoparticles with uniform size are considered ideal heterogeneous catalytic materials. However, understanding how the composition and morphology of alloys made from metals with significantly different reduction potentials affect catalytic performance remains a challenge in bimetallic systems. In this study, we present a novel process for synthesizing uniform Cu_xPd alloy nanoparticles supported on graphene (Cu_xPd/G). This process involves homogeneously mixing palladium (Pd) and copper (Cu) metal precursors with graphene powder, followed by thermal decomposition in a carbon monoxide atmosphere at 300 °C. Despite the significant difference in reduction potentials between Cu and Pd, we successfully synthesized Cu₃Pd alloy nanoparticles with a clean surface and an average size of approximately 16 nm through a simple and rapid thermal treatment process, without the use of surfactants. The Cu₃Pd/G catalyst demonstrated excellent catalytic performance in the domino Sonogashira cyclization reaction, achieving a high conversion rate of 95%. In contrast, palladium nanoparticles supported on graphene (Pd/G) and other alloy compositions exhibited only moderate catalytic performance, with conversion rates of 78% for Pd/G, 84% for CuPd/G, and 66% for Cu₅Pd/G.