Tailoring the Pore Size and Architecture of CeO2/TiO2 Core/Shell Inverse Opals by Atomic Layer Deposition

Colloidal crystal templates and atomic layer deposition (ALD) were combined to generate inverse opal CeO2/TiO2 core-shell structures with precisely defined pore size and architectures. Three-dimensionally ordered macropores (3DOM) CeO2 sampled were prepared as inverse replicas of polystyrene colloidal crystals and the CeO2 inverse opals were coated with TiO2 overlayers grown by ALD. The average size of the CeO 2 crystallites is estimated to be 6nm, which accounts for the mild conditions used during removal of the polymer templates. The deposition of TiO2 layers began from the walls of the inverse opals, and the void spaces, which result from the deposition process. ALD is found to yield core-shell inverse opal structures characterized by a uniform, full coverage of the core part.