Synthesis and characterization of hydrogen-selective sol-gel SiO2 membranes supported on ceramic and stainless steel. supports

Novel microporous membranes were developed on porous ceramic and stainless steel supports to separate H-2 from CO2 or N-2. An extensive synthesis and characterization study was carried out, which yielded novel processing routes for microporous membranes. Examples in this article include rapid thermal processing (RTP), ink-jet printing, and a route for fabricating metal-supported microporous membranes. Pure SiO2 membranes prepared under optimized cleanroom conditions exhibited a reproducible high selectivity for He and H-2 towards CO2 and N-2 (e.g. average alpha(H2/CO2) > 70; alpha(H2/N2) > 150). Microporous membranes prepared with RTP, with an overall processing time of approximately 1 h for the microporous top layer, showed a similar gas permeance and high selectivity. Another breakthrough compared to the state of the art is the introduction of a gas-selective metal-supported microporous membrane. The first prototypes, which were fabricated with a commercial stainless steel filter material as support material, exhibited a comparably attractive selectivity for H-2 (e.g. alpha(H2/CO2) similar to 50). Ni- and Co-doped membranes were additionally prepared in this study, since they are recognized as a membrane type with improved stability towards water vapour. (C) 2013 Elsevier B.V. All rights reserved.