Pd–Cu alloy membrane deposited on CeO2 modified porous nickel support for hydrogen separation

• Porous nickel support was modified by ceria successfully.
• Defect-free 7 μm thick Pd93–Cu7 layer was deposited by sputtering and Cu-reflow method.
• H2/He selectivity was >50,000 at a temperature of 773 K and ΔP = 400 kPa.

In this study, the hydrogen permeation behavior of a Pd93–Cu7 alloy membrane deposited on ceria-modified porous nickel support (PNS) was evaluated. PNS, which has an average pore size of 600 nm, was modified by alumina sol. Alumina sol was prepared using precursors that had a mean particle size of 300 nm. Alumina-modified PNS was further treated with ceria sol modification to produce a smoother surface morphology and narrow surface pores. A 7 μm thick Pd93–Cu7 alloy membrane was made on an alumina-modified PNS and a ceria-finished membrane was fabricated by magnetron sputtering followed by Cu-reflow at 700 °C for 2 h. SEM analysis showed that the membrane deposited on a ceria-finished PNS contained more clear grain boundaries than the membrane deposited on the alumina-modified PNS. The membrane was mounted in a stainless steel permeation cell with a gold-plated stainless steel O-ring. Permeation tests were then conducted using pure hydrogen and helium at temperatures ranging from 673 to 773 K and feed side pressures ranging from 100 to 400 kPa. These tests showed that the membrane had a hydrogen permeation flux of 2.8 × 10−1 mol m−2 s−1 with H2/He selectivity of >50,000 at a temperature of 773 K and pressure difference of 400 kPa.