Preparation of a large Mesoporous CeO2 with crystalline walls using PMMA colloidal crystal templates

Inverse opals of crystalline CeO2 were synthesized by using close-packed poly(methyl methacrylate) (PMMA) latex spheres of various sizes as templates, resulting in pore sizes, which could be scaled down even to the mesopore region (30–40 nm). The latex spheres were synthesized by emulsion polymerization, and the PMMA particle size could be substantially decreased by addition of sodium dodecyl sulfate (SDS) as surfactant. Owing to the larger pore wall thickness, the CeO2 with large mesopores preserves an intact porosity to higher temperatures than previously reported mesoporous CeO2 obtained from surfactant templates. The porosity and crystallinity were studied by microscopic techniques, wide angle X-ray diffraction (XRD), N2 sorption, and Hg porosimetry. The evolution of crystallinity (crystallite size and lattice parameters) was determined for different annealing temperatures by means of Rietveld refinements of the XRD data. Thereby, our study allowed getting general insights into the crystallization behavior of sol–gel derived porous CeO2 frameworks.