Next-generation mesoporous cerium oxide scaffolds are synthesized for the fabrication of highly performing solid oxide cells by introducing a hard-template nanocasting synthesis route which comprises chemical post-treatments.

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This research is focused on the study of the samples, approximatively 15 9 30 mm 2 sized, that were mechanically cut from two sheets (0.4 and 0.2 mm thick, respectively) of AISI 444 Type ferritic stainless steel (FSS) (DIN 1.4521, Eu designation X2CrMoTi18-2); this material was in the 'as-rolled' state. Part of these specimens were treated superficially on one side using abrasive SiC papers with different average grit sizes (i.e., 46.2, 30.2, 18.3 lm) and diamond suspension (up to 1 lm) in order to obtain various surface roughness. Both the 'as-rolled' and superficially treated samples were then aged in a muffle furnace in static air according to a thermal cycle corresponding to the curing phase of an experimental glass used as sealing in the solid oxide fuel cell stacks. After aging, the chemical compositions and morphological peculiarities of the scale formed depending on the thickness of the samples and their surface state were studied by scanning electron microscopy, energy-dispersive spectroscopy, micro-Raman spectroscopy, bright field light optical microscopy. The obtained results show that all scales formed consist of an inner Cr 2 O 3 subscale and an outer (Mn,Cr) 3 O 4 spinel layer; the relationship between FSS grain size and scale microstructural features is consistent on the samples with mirror-like surface only; the scale thicknesses on SiC grinded samples are comparable; the scales covering the 'as-rolled' surfaces are morphologically similar to those grown on the surfaces finished with the 30.2 and 18.3 lm SiC papers, and their thicknesses show an intermediate situation between the abraded and the mirror-like specimens. The last described characteristics depend mainly on the surface and microstructural peculiarities resulting from the rolling process.

Hard-template nanocasted mesoporous cerium oxide possesses a unique combination of thermal stability, high surface area, and short diffusion lengths for mass and gas transport, which makes it relevant for high-temperature catalysis, sensing, and electrochemical applications. Here, we present an in-depth study of a number of mesoporous doped ceria systems, and we assess their fundamental structure and functionalities by complementary transmission electron microscopy imaging and spectroscopy, electron tomography reconstructions, and electrochemical impedance spectroscopy. We employed surface chemical modifications for increasing the ionic conductivity of as-synthesized mesoporous Gd-doped ceria by 2 orders of magnitude, enabling the ionic pathway across mesoporous particles. Complementary bulk doping strategies (by the addition of Pr) result in the easy tuning of the electrical transport mechanisms converting pure ionic mesoporous ceria into a mixed ionic–electronic conductor. The results obtained here are rationalized in light of local charge accumulation and mobility effects, providing a potential tool for engineering transport properties in nanocasted ceria and similar nanostructured materials for use in energy applications in the form of functional composites, infiltrated structures, or catalytic layers.