The effect of CO on hydrogen permeation through Pd and through internally oxidized and un-oxidized Pd alloy membranes

Pd alloy permeation membranes such as Pd–Al and Pd–Fe which have been internally oxidized are more resistant to inhibition by CO(g) than Pd or un-oxidized alloy membranes. The increased resistance to CO is found to be greater at 423 K than at 473 K or 523 K. In these experiments CO was pre-adsorbed onto the membranes and then H2 was introduced to initiate the H permeation.

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► Flux is directly proportional to 1/(membrane thickness) for Pd and Pd0.77Ag0.23 membranes but not for membranes in the presence of CO.
► H flux of internally oxidized Pd alloy membranes compared in the presence and absence of CO.
► CO inhibition of internally oxidized Pd–Al and Pd–Fe alloys membranes is found to be smaller for internally oxidized alloys than for un-oxidized membranes with the same flux.
► Internally oxidized Pd–Y alloy membranes do not have increased resistance to CO.