Mesostructured Crystalline Ceria with a Bimodal Pore System Using Block Copolymers and Ionic Liquids as Rational Templates

A concept is shown to fabricate mesoporous ceria thin films with a crystalline framework and a bimodal pore size distribution by evaporation-induced self-assembly followed by a suitable temperature treatment and template removal strategy. The use of a suitable block copolymer ((CH 2 CH 2 CH 2 (CH)CH 2 CH 3 ) 79 (OCH 2 CH 2 ) 89 OH), “KLE”) and an ionic liquid template (leading to pores 3 nm in diameter) generated a bimodal pore system of deformed spherical mesopores of ca. 6 nm × 16 nm with the smaller pores being located in the matrix between the larger ones. The porosity was studied by a combination of quantitative SAXS analysis, physisorption, AFM, and TEM, introducing a general methodology for a quantitative structural characterization of such films.