Palladium (Pd) and palladium alloy membranes have been
extensively investigated for hydrogen separation due to their
high permselectivity and good thermal and chemical stabilities
.
This separation technology can be coupled with a
wide range of catalytic reactions, known as a membrane
reactor, and it is crucial for energy applications.
Palladium alloy membranes can be either self-supported or supported
by a substrate (composite membrane configuration) in
the form of tubes or flat discs.
In early studies, Pd membranes were mainly self-supported with a high thickness, to ensure a
reasonable mechanical strength, and presented low hydrogen
(H2) permeability and high material cost.
Currently, research has been mostly focused towards the development of highly
permselective Pd and Pd-alloy composite membranes with
suitable mechanical strength and reduced membrane thickness.
The use of a porous support (i.e. a ceramic, a metallic or a
glass support), acting as a scaffold, provides additional
structure and mechanical strength.
Meanwhile, the thickness of the membrane can be significantly reduced, resulting in
higher permeation flux and less material cost.
The selection of the substrate is crucial and based on its morphological
properties, such as pore size, pore size distribution, pore
structure, porosity, roughness of substrate and mechanical,
thermal and chemical stabilities.
Therefore, the development of high quality composite Pd membrane is strongly
dependent on the achievement of a thin and highly permselective
membrane, which is largely determined by the selection
of a porous substrate with high surface area and
negligible permeation resistance.
Palladium (Pd) and palladium alloy membranes have beenextensively investigated for hydrogen separation due to theirhigh permselectivity and good thermal and chemical stabilities. This separation technology can be coupled with awide range of catalytic reactions, known as a membranereactor, and it is crucial for energy applications. Palladium alloy membranes can be either self-supported or supportedby a substrate (composite membrane configuration) inthe form of tubes or flat discs. In early studies, Pd membranes were mainly self-supported with a high thickness, to ensure areasonable mechanical strength, and presented low hydrogen(H2) permeability and high material cost. Currently, research has been mostly focused towards the development of highlypermselective Pd and Pd-alloy composite membranes withsuitable mechanical strength and reduced membrane thickness.The use of a porous support (i.e. a ceramic, a metallic or aglass support), acting as a scaffold, provides additionalstructure and mechanical strength. Meanwhile, the thickness of the membrane can be significantly reduced, resulting inhigher permeation flux and less material cost. The selection of the substrate is crucial and based on its morphologicalproperties, such as pore size, pore size distribution, porestructure, porosity, roughness of substrate and mechanical,thermal and chemical stabilities. Therefore, the development of high quality composite Pd membrane is stronglydependent on the achievement of a thin and highly permselective
membrane, which is largely determined by the selection
of a porous substrate with high surface area and
negligible permeation resistance.
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