Studies of self-supported 1.6μm Pd/23wt.% Ag membranes during and after hydrogen production in a catalytic membrane reactor

Microstructural characterization of self-supported 1.6μm Pd/Ag membranes

“…In M400, the flux first increased from about 0.075 mol/(m 2 s) to 0.082 mol/(m 2 s) during the first 2.5 h, before decreasing to 0.054 mol/(m 2 s) after 10 h. It then increased almost linearly to 0.060 mol/(m 2 s) at 27 h where the experiment was terminated before reaching steady state. The above values can be compared to the maximum flux of 0.15 mol/(m 2 s) possible under these conditions, obtained through repeated experiments conducted on freshly prepared 1.6 m Pd/Ag membrane assemblies [10].…”

“…The total exposed area was about 2.40 cm 2 . The membrane configuration utilized is described in detail elsewhere [10]. Three membranes tested under a typical WGS reactant/product mixture at 300, 350 and 400 • C, labeled M300, M350 and M400, respectively.…”

“…To the best of our knowledge, the latter value is the highest ever reported for a dense 100% selective metallic membrane. Such thin, self-supported membranes are also suited for studying the influence of surface processes on transport as well as structural changes, since the bulk is not rate controlling under all conditions, and the possible influence of a porous support is eliminated [10].…”

Fabrication of novel Pd–Ag–Ru/Al2O3 ternary alloy composite membrane with remarkably enhanced H2 permeability

“…Dense Pd membrane permeates only hydrogen and it has been still the metal membrane with the highest permeability and selectivity for hydrogen permeation. In particular, ultra-pure hydrogen can be obtained in one step by using a Pd-based membrane reactor to integrate hydrogen separation process with the hydrogen-producing reactions including dehydrogenation reactions [9][10][11] and reforming reactions [12][13][14][15] of methane or other hydrocarbons. The material cost can be minimized and hydrogen permeation rates can be maximized by coating of thin Pd film onto highly hydrogen permeable supports such as porous ceramics, metal oxides and metallic materials.…”

Characterization of Pd–Ag membranes after exposure to hydrogen flux at high temperatures

“…Only a few studies have been reported employing XPS for surface characterization of the Pd-Ag alloy membranes [28,29]. However, this technique allows characterization of the surface of palladium alloy membranes after the interaction with hydrogen.…”