Freeze cast support for hydrogen separation membrane

BaCe0.65Zr0.20Y0.15O3-delta - Gd0.2Ce0.8O2-delta (BCZY-GDC) membranes have received increasing attention for their full H-2 selectivity, high thermal and chemical stability, and intrinsic lower cost respect the Pd-based technology. The microstructure of the substrate plays a fundamental role to increase the gas diffusivity through the porous support. In this work, BCZY-GDC ceramics for hydrogen separation application were produced for the first time using ice-templating technique to obtain membrane supports with well-organized aligned porosity and lower pore tortuosity. After slurry composition optimization, the effect of cooling rate on the microstructure was accurately investigated. Samples produced with cooling speed of 30 degrees C/h showed homogeneous microstructures and well-aligned porosity with the best compromise between gas permeability and mechanical properties. Particularly gas permeability values are one order of magnitude higher with respect to the ones registered for tape cast BCZY-GDC substrates with isotropic porosity conventionally used for protonic applications.