Ni2O3-around-Pd hybrid on graphene oxide: An efficient catalyst for ligand-free Suzuki–Miyaura coupling reaction

• Ni2O3 isolated Pd clusters was prepared on the surface of graphene.
• Highly dispersed Pd (2.5 nm) could be generated by adjustment of Ni to Pd ratio.
• Ni2O3 isolated Pd exhibited higher activity for Suzuki coupling reactions.
• Ni2O3 has multiple roles in exfoliating graphene, mediating size and stability of Pd.
• Reactant enrichment and intimate interaction of metals lead to excellent activity.

Ni2O3-around-Pd hybrid can be fabricated on graphene oxide (Pd–Ni/RGO) by a simple one-pot wet chemical route. These isolated Pd clusters showed significantly improved performance for Suzuki coupling reaction compared to that of pure Pd/RGO, Ni2O3/RGO, popularly reported Pd/AC, as well as homogeneous PdCl2 and PdCl2(PPh3)2. Characterizations disclosed that Ni2O3 plays multiple roles in exfoliating graphene sheets, mediating the size as well as stability of Pd clusters. Pd–Ni/RGO dispersed homogeneously in the aqueous reaction mixture, exhibited high enrichment towards reactants as well as extremely high activity and stability for the Suzuki coupling reaction. The best turnover frequencies of all Pd atoms reached 38,750 h−1 at 80 °C for bromobenzene coupling. It was concluded that the intimate interaction between Ni2O3 nanoparticles and Pd clusters appears to be beneficial for activating the Pd surface for the catalytic cycle.

Figure optionsDownload high-quality image (216 K)Download as PowerPoint slide