Efficient aqueous media Suzuki-Miyaura cross-coupling reaction using ligand-free and environmentally-friendly palladium-doped ceria-zirconia mixed metal oxide nanocatalyst

A palladium ceria-zirconia Pd0.05Ce0.5Zr0.475O2 catalytic based nanomaterial was produced by co-precipitation method. To compare the effect of each atom, Pd0.1Ce1.45O3 and Pd0.1Zr1.45O3 were synthesized. Several techniques were used (TGA, XRD, N2 adsorption/desorption (BET theory), XPS, SEM and TEM and HR-TEM microscopy) to characterize the samples. Pd0.05Ce0.5Zr0.475O2 exhibits the highest BET surface area, 117 m2/g compared to the two mentioned materials. According to XRD and XPS analysis, the oxidation state of palladium was +2 in this oxide. Compared to other materials, Pd0.05Ce0.5Zr0.475O2 was the most efficient catalyst for a wide range of aryl bromides and aryl boronic acids in aqueous media without the use of any ligand. Very good yields were achieved and could easily reach a value of 93% in the case of iodobromides. Pd0.05Ce0.5Zr0.475O2 showed also a good stability and could be easily separated and reused with high catalytic activity after three cycles. In addition, no leaching of Pd2+ was observed which confirmed the highly heterogeneous nature of our catalyst.

Automated summary

A palladium ceria-zirconia Pd0.05Ce0.5Zr0.475O2 catalytic based nanomaterial was synthesized and characterized. Compared to other materials, Pd0.05Ce0.5Zr0.475O2 exhibited the highest BET surface area and showed high catalytic activity and stability for aryl bromides without the use of any ligand.