Monodispersed Pd clusters generated in situ by their own reductive support for high activity and stability in cross-coupling reactions

Uniform 3D flower-like hierarchical-structured CoAl-LDH spheres were prepared via a simple one-pot surfactant-free solvothermal method. Monodispersed tiny Pd nanoclusters (about 2 nm) were loaded on the CoAl-LDH support through a facile in situ reduction between the oxidative Pd precursors and the reductive Co(II) in the support. The resultant CoAl-LDH/Pd composite catalyst showed excellent activities in cross-coupling reactions. In addition, the abundant Co(II) sites in the support can efficiently capture and regenerate leached Pd species during the reaction process, leading to excellent stability of the composite. These two features are desirable in organic synthesis, and may be used on a large scale for cross-coupling reactions with lower cost and easier operation.