Hydrogen separation

A method for producing a composite membrane for separating hydrogen molecules from a gas stream, the method comprising:

• disposing a first metallic layer on a porous substrate, wherein the porous substrate has a pore structure configured to allow diffusion of hydrogen molecules through the porous substrate, and the first metallic layer comprises palladium;
• disposing an intermediate layer on the first metallic layer, wherein the intermediate layer comprises at least one of graphene or graphene oxide;
• disposing a second metallic layer on the intermediate layer, wherein the first metallic layer, the intermediate layer, the second metallic layer, and the porous substrate form the composite membrane, and the second metallic layer comprises palladium;
• and
• treating the composite membrane with heat to equalize thickness and composition of the composite membrane;
• wherein the porous substrate is metallic, the method further comprises disposing an interlayer on the porous substrate prior to disposing the first metallic layer, the interlayer comprises at least one of aluminum oxide, zirconium oxide, cerium oxide, or silicon oxide, and disposing the first metallic layer on the porous substrate comprises disposing the first metallic layer on the interlayer that has been disposed on the porous substrate.

A method comprising:

• contacting a gas stream comprising hydrogen molecules with a surface of a composite membrane comprising a porous substrate and a multi-layer membrane, wherein the multi-layer membrane comprises a first metallic layer comprising palladium, an intermediate layer comprising at least one of graphene or graphene oxide, and a second metallic layer comprising palladium;
• and
• separating, by the composite membrane, at least a portion of the hydrogen molecules from the gas stream, wherein separating at least the portion of the hydrogen molecules from the gas stream comprises:
• splitting, by the multi-layer membrane, at least the portion of the hydrogen molecules into at least one of hydrogen atoms or protons in response to contacting the gas stream;
• and
• preventing, by the multi-layer membrane, passage of compounds that may be present in the gas stream that are larger than hydrogen molecules while allowing passage of the hydrogen atoms or protons through the multi-layer membrane;
• wherein the porous substrate is metallic, and the multi-layer membrane is coupled to the surface of the porous substrate by an interlayer comprising at least one of aluminum oxide, zirconium oxide, cerium oxide, or silicon oxide.