Hollow Microporous Cerium Oxide Spheres Templated By Colloidal Silica

We present a simple, solution-based synthetic route to hollow cerium oxide spheres. Thin layers (∼12 nm) of cerium oxide are deposited onto ∼200 nm silica colloids using cerium nitrate and the silica cores are subsequently removed to yield hollow spheres. The spheres are composed of ∼4 nm ceria nanocrystals. Nitrogen adsorption isotherms indicate that the spheres are microporous with pore sizes of approximately 10 Å. The spheres are thermally stable to collapse and ripening up to 700 °C and are active for the catalytic combustion of carbons. The hollow ceria spheres developed in this work are attractive as building blocks for multicomponent catalysts.