Preparation of Thin Palladium Composite Membranes and Application to Hydrogen/Nitrogen Separation*

Thin palladium composite membranes were prepared by modified electroless plating method on α-alumina supports and a dense Pd/α-Al2O3 composite membrane with high hydrogen flux, good selectivity for hydrogen was obtained. It was tested in a single gas permeation system for hydrogen permeance and hydrogen selectivity over nitrogen. The hydrogen permeance of the corresponding membrane was as high as 2.45 × 10−6mol · m−2 · s−1 · Pa−1 and H2/N2 selectivity over 700 at 623K and a pressure difference of 0.1MPa. The main resistance of the composite membrane to H2 permeation lies in the aluminum ceramic support rather than the thin Pd layer.