Preparation of a novel Pd/layered double hydroxide composite membrane for hydrogen filtration and characterization by thermal cycling

A layered double hydroxide (LDH) layer was grown directly on a porous stainless steel (PSS) surface to reduce the pore opening of the PSS and to be a middle layer retarding Pd/Fe interdiffusion. A thin Pd film (∼7.85 μm) was plated on the modified PSS tube by an electroless plating method. A helium leak test proved that the thin Pd on the LDH-modified PSS substrate was free of defects. The membrane had a H2 flux of 28-36 m3/(m2 h) and H2/He selectivity larger than 2000 at a pressure difference of 1 bar. Thermal cycling between room temperature and 673 K was performed and showed that the membrane exhibited good permeance and selectivity. Long-term evaluation (1500 h) of the membrane at 673 K showed static results of H2 flux (∼30 m3/(m2 h)) and H2/He selectivity (∼2000) over the 1500 h test period.