Pd membrane with excellent stability was prepared on macroporous alpha-Al2O3 tubes using a nanoporous Sil-1 zeolite as an intermediate support and diffusion barrier layer The detailed microstructure of the composite membrane was examined by scanning electron microscopy and mapped by EDXS and EPMA to reveal a palladium membrane anchored by multi-legs Pd protrutions that penetrates through the interstices of the zeolite grains into the seed layer This membrane architecture allowed the membrane to tolerate rapid and repeated cycling of gases, temperature and pressure over 300 h without lost of permeance and selectivity. The zeolite layer contributed up to 25% of the transport resistance across the Pd-Sil-1 composite membrane and has a significant effect on the hydrogen permeance (C) 2010 Elsevier B V All rights reserved