Design, Synthesis, Structural and Textural Characterization, and Electrical Properties of Mesoporous Thin Films Made of Rare Earth Oxide Binaries

Ceria-based oxides are of interest as electrolyte and electrode materials in intermediate-temperature solid-oxide fuel cell (SOFCs). A sol−gel strategy has been developed for the production of mesoporous, nanostructured, single phase Ln 0.1 Ce 0.9 O 2, Ln = La, Y, Sm, Gd, Dy thin films. The ceria-based mesoporous thin films exhibit high specific area, periodic through-connected networks of mesopores (∼20 nm), and continuous networks of nonagglomerated nanoparticles (15 nm). Calcination at relatively mild temperature for this oxide (300 °C) converts the amorphous films to nanocrystalline fluorine Ln 0.1 Ce 0.9 O 2 . Although densified during calcination, the mesoporous nanoarchitectures retain porosity, high surface area, and limited particle agglomeration. The electrical properties of mesoporous thin films are evaluated from 400 to 500 °C in air. The conductivity of these mesoporous thin films is comparable to the one observed for dense ceramic containing particles in the nanometer range, reflecting that the interparticulate junctions are not restrictive for the transport of oxide-ion vacancies. A high degree of interconnectivity has been established between the nanocrystallites (<15 nm) in these mesoporous thin films, yielding electroceramic films where the grain boundaries are not restrictive for the oxygen ion transport. This study provides processing guideline to achieve fabrication of 3-D mesostructured thin films for efficient interface in SOFC.