Preparation of dense Pd composite membranes on porous Ti–Al alloy supports by electroless plating

Dense Pd/TiO2/Ti–Al alloy composite membranes on porous Ti–Al alloy supports were prepared by electroless plating. The TiO2 membrane was applied as an inter-diffusion barrier between the Pd layer and the Ti–Al alloy support to prevent intermetallic diffusion. Electron probe microanalysis (EPMA) and EDX cross-sectional line scans showed that the intermediate layer was effective as the diffusion barrier for Pd membranes on Ti–Al alloy supports after 40 h of treatment at 973 K in pure hydrogen. The thickness of the resulting Pd composite membrane was approximately 14 μm. The hydrogen permeance through the Pd composite membrane was 1.07 × 10−3 mol m−2 s−1 Pa−0.5 at 773 K. The permeance and selectivity of the Pd composite membrane were measured at different temperatures and pressures. The permeance tests showed that the Pd/TiO2/Ti–Al alloy composite membranes have high H2/N2 selectivity. In addition, heat cycles indicated that the structure of the Pd composite membranes was stable.