Nanostructured ceramic membranes for hydrogen separation☆

Hydrogen separation membranes are cornerstone technologies for advancing the practical development of the hydrogen sector. Mixed ionic-electronic conductors (MIEC) based on BaCexZryY1-x-yO3-gamma (BCZY) perovskites and CezGd1-zO2-delta (GDC) fluorite have gained increasing attention for their high conductivity and selectivity, temperature and chemical stability. However, hydrogen permeation fluxes reached until now are still too low for industrial applications (compared to metal-based or cer-met composites). One strategy to improve the separation performances is to enhance the catalytic activity by applying a nanostructured coating on the whole membrane surface, to increase the overall surface area of the membrane and provide for a better catalyst dispersion. This study aims to establish a reproducible and eco-friendly methodology for applying nanostructured BCZY-GDC porous coatings onto symmetric cer-cer membranes via dip-coating in aqueous suspensions, and investigate their influence on the hydrogen separation ability. It was found that hydrogen permeated flux increases by more than 2 times when a 3.5 mu m porous coating was applied to both sides of the membranes, thanks to the better distribution of Pt catalytic particles. No signs of degradation or structural modification were observed on the porous coating after permeation.