A composite palladium and porous aluminum oxide membrane for hydrogen gas separation

Thin Composite Palladium and Palladium/Alloy Membranes for Hydrogen Separation

“…The porous supports used by various investigators comprised porous alumina and glass, and porous metals including porous Ni and porous stainless steel. Some of the techniques used for the deposition of Pd or its alloys on a support were the spray pyrolysis method to deposit Pd‐Ag alloy on an alumina support,5 the metal‐organic chemical vapor deposition (MOCVD) technique by decomposing palladium (II) acetate in argon under a reduced pressure to form a thin palladium membrane inside the porous wall of an α‐alumina tube,6,7 the supercritical fluid transport‐chemical deposition (SFTCD) method using the metal β‐diketonate complex, (2,2,7‐trimethyl‐3,5‐octanedionato) palladium (II), to pyrolytically deposit a thin 1–2μm Pd layer,8 the sputter‐deposition technique to deposit an ultrathin Pd layer on polymeric membranes,9 porous alumina,10,11 anodic alumina,12,13 and Vycor glass,14 magnetic sputtering to deposit Pd and Pd‐alloys on polymer membranes, porous stainless steel, and oxide plates,15 and electron beam evaporation and ion‐beam sputtering to deposit Pd on the surface of tantalum foil 16. Some other examples of the application of these techniques, as well as physical vapor deposition and electroplating, are briefly discussed in the review by Shu et al 17 The major drawbacks of all these powerful techniques, that are especially useful for the deposition of alloys, are low area of the prepared membranes and/or high cost of the necessary equipment.…”

Defect‐free palladium membranes on porous stainless‐steel support

“…A thin (1-2 pm) Pd layer was also pyrolytically deposited by the supercritical fluid transport-chemical deposition (SFTCD) method using the metal P-diketonate complex-(2,2,7-trimethyl-3,5-octanedionato) palladium (11) (Hybertson et al, 1991). Ultrathin Pd composite membranes were prepared by the sputter-deposition technique on polymeric membranes (Athayde et al, 1994), porous alumina (Jayaraman et al, 1995a, b), anodic alumina (Konno et al, 1988;Mardilovich et al, 1996a), and Vycor glass (Bryden and Ying,199.5) supports. Gryaznov et al (1993) prepared Pd and Pd-alloy membranes on polymer membranes, porous stainless steel, and oxide plates by magnetic sputtering.…”

Bismuth quantum-wire arrays fabricated by a vacuum melting and pressure injection process

“…Anodic alumina has previously been used to synthesize a variety of metal and semiconductor nanowires, such as Ni, Pd, Au, Pt, and CdS, through chemical or electrochemical processes. [4][5][6][7] However, the diameters of those nanowires have not reached the quantum confinement regime. In order to exhibit strong quantum confinement characteristics, the wire diameter should be smaller than the exciton diameter, which is given by d ex 2eh 2 (m 21 e 1 m 21 h )͞e 2 , where e is the static dielectric constant, and m e and m h are the effective masses of electrons and holes, respectively.…”