Experimental Demonstration of Enhanced Hydrogen Permeation in Palladium Via a Composite Catalytic-Permselective Membrane

A composite catalytic-permselective (CCP) membrane comprised of a 500-mu m Cu(II)O/Al2O3 catalyst film washcoated overtop a 27-mu m electroless-plated dense palladium thin film was constructed on a porous less-steel substrate. Hydrogen purification experiments performed under ideal (H-2-Ar) nonreactive mixtures and simulated reformate (5% CO, 7.5% H2O, 15% H-2, 1.5% CO2, and balance Ar) over a range of residence times at 623-773 K confirm up to 30% enhancement in observed hydrogen permeance of the palladium film, achieved using the CCP membrane design in which the catalyst layer modifies the gas-phase composition in direct contact with the permselective Pd film. Scanning electron microscopy analysis of the palladium film after similar to 10-h exposure to reaction conditions and Cu(II)O catalyst confirm no corrosion of the film, while observed hydrogen permselectivities remained in excess of 10,000:1. These experimental results confirm that the CCP membrane design is capable of significantly improving palladium membrane performance. (C) 2012 American Institute of Chemical Engineers AIChE J, 59: 1627-1634, 2013