Supported High Temperature Protonic Films Produced by Solid State Reaction

Abstract

AbstractThis work presents the last progresses in the development of thin oxidic proton conducting electrolytes supported on mixed conducting cermets making use of a solid state reaction. The procedure includes preparation routes applying solid state transformation of an already-gastight oxide layer (typically doped zirconia and ceria) by reacting with an alkali-earths layer (stoichiometric amount) deposited by screen printing on top of that. This kind of supported films can find application as IT-SOFC, H2-membranes and advanced catalytic converters. Thin-film (∼5μm) proton conducting membranes with the nominal composition as for instance BaZr0.85Y0.15O3-δ and BaCe0.8Gd0.2O3-δ were prepared over porous Ni-8YSZ or Ni-CGO substrates by solid state reaction. The produced films are gastight with a homogeneous composition, and showed a highly crystalline cubic perovskite structure. The solid state reaction promoted the formation of (i) a different grain size distribution from 0.1 μm for barium zirconate to 2-3μm for barium cerate, and (b) the formation of a porous fibrous top-layer (for barium zirconate) or a just flat surface (for strontium zirconate), depending on the exact composition of the reacting oxides.