Gram-Scale Synthesis of Magnetically Separable and Recyclable Co@SiO2 Yolk-Shell Nanocatalysts for Phenoxycarbonylation Reactions

Co@SiO2 yolk-shell nanostructures were fabricated on a gram scale by simple hydrogen reduction of CoO@SiO2 core-shell nanoparticles without using an etching step. The cobalt core diameters were reduced by the lattice volume contraction of CoO to Co, forming vacancy between the cores and the silica shells. The Co@SiO2 yolk-shell nanocatalysts were employed for the phenoxycarbonylation of iodobenzene, and exhibited high activity and reusability. The magnetic property of the cobalt cores enabled the facile separation of catalysts from the products.