PdAg/alumina membranes prepared by high power impulse magnetron sputtering for hydrogen separation

The development of hydrogen purification membranes that meet market demands such as
high purity, dynamic hydrogen production even at small scale, and reduced costs is still an
open question. With this view, the present study aims at developing, for the first time, a
method based on high power impulse magnetron sputtering for the deposition of Pd77Ag23
(wt%) films onto porous alumina substrates to achieve composite membranes with high
hydrogen permeability and stability. This technique allows the deposition of films also on
complex geometries and can be easily scaled up, thus making this technology a potential
candidate for preparing high performing membranes. Membranes made by stable and
porous alumina supports and metallic, dense and crystalline Pd77Ag23 layers, from 3.5 mm
to 17 mm thick, have been prepared and tested. The membranes showed good hydrogen
permeability values, showing flux values up to a maximum of 0.62 molH2 m2 s1 at 450 C
and DP of 300 kPa. The resistance to hydrogen embrittlement and the chemical inertness to
syngas were also demonstrated.