Open AccessPROTON-CONDUCTING DENSE CERAMIC MEMBRANES FOR HYDROGEN SEPARATION
Author(s) -
Jerry Y S Lin,
Scott Cheng,
Vineet Gupta
Publication year - 2003
Language(s) - English
Resource type - Reports
DOI - 10.2172/822716
Subject(s) - hydrogen , permeation , membrane , permeance , materials science , partial pressure , sputtering , annealing (glass) , hydrogen purifier , analytical chemistry (journal) , chemical engineering , alloy , ceramic , thin film , chemistry , oxygen , metallurgy , nanotechnology , hydrogen production , chromatography , biochemistry , organic chemistry , engineering
Dense perovskite-type structured ceramic membranes, SrCe{sub 0.95}Tm{sub 0.05}O{sub 3} (SCTm), of different thickness, were prepared by the dry-press method. Membrane thickness was varied from 3 mm to 150 {micro}m. The hydrogen permeation flux was found to be inversely proportional to the thickness of the dense films, indicating that the bulk diffusion rather than the surface reaction played a dominant role in the H{sub 2} transport through these dense membranes within the studied thickness range. Hydrogen permeation flux increases with increasing upstream hydrogen partial pressure and decreasing downstream hydrogen partial pressure. The activation energy for hydrogen permeation through the SCTm membrane is about 116 kJ/mol in 600-700 C and 16 kJ/mol in 750-950 C. This indicates a change in the electrical and protonic conduction mechanism at around 700 C. Pd-Cu thin films were synthesized with elemental palladium and copper targets by the sequential R.F. sputter deposition on porous substrates. Pd-Cu alloy films could be formed after proper annealing. The deposited Pd-Cu films were gas-tight. This result demonstrated the feasibility of obtaining an ultrathin SCTm film by the sequential sputter deposition of Sr, Ce and Tm metals followed by proper annealing and oxidation. Such ultrathin SCTm membranes will offer sufficiently high hydrogen permeance for practical applications