Effective H₂ Separation through Electroless Pore-Plated Pd Membranes Containing Graphite Lead Barriers

Area of Science:

• Materials Science
• Chemical Engineering
• Energy Technology

Background:

• Hydrogen is a key clean energy vector for decarbonization.
• Palladium-based membranes are crucial for H2 purification in production processes.
• Porous stainless steel (PSS) supports offer advantages for membrane fabrication.

Purpose of the Study:

• To develop and characterize novel composite membranes for hydrogen purification.
• To evaluate the performance of palladium films on graphite-modified PSS supports.
• To assess the mechanical stability and operational reversibility of the membranes.

Main Methods:

• Fabrication of composite membranes using electroless pore-plating of palladium onto graphite-modified PSS supports.
• Characterization of palladium layer density and thickness.
• Hydrogen and nitrogen permeation measurements in both in-out and out-in configurations.
• Analysis of H2/N2 mixture permeance and evaluation of Sieverts' law adherence.

Main Results:

• Fully dense palladium layers (approx. 17 μm) were achieved on the modified PSS supports.
• High H2/N2 selectivity (α ≥ 10,000) and permeance (3.24–4.33 × 10^-4 mol m^-2 s^-1 Pa^-0.5) were obtained at 350-450 °C.
• Minor deviations from Sieverts' law were observed due to pore infiltration; H2 permeance decreased by ~33% with 40% N2 due to concentration polarization.
• Membrane performance remained stable after reversing the permeate flux direction, indicating good mechanical resistance.

Conclusions:

• The developed composite membranes exhibit excellent H2 purification performance and selectivity.
• The graphite interlayer and pore-plating method enhance palladium layer integrity and membrane stability.
• These membranes demonstrate robust mechanical properties and operational reversibility, suitable for demanding hydrogen separation applications.