Ni/alumina composite membranes were prepared and investigated for hydrogen separation at high temperature. α-Alumina-supported γ-alumina composite membranes were prepared by soaking-rolling method. In order to improve H2 selectivity and permeance of the γ-alumina membranes, Ni was deposited by a soaking process. As a result of a single gas permeation test of the Ni/alumina composite membranes, hydrogen permeance and H2/N2 selectivity at permeation temperature of 450 °C were 6.29 × 10-7 mol / m2 s Pa and 5.2 which exceeded theoretical Knudsen selectivity. Contribution of surface diffusion was investigated by temperature dependence of H2 permeance. The surface diffusion was observed at higher temperature above 250 °C. The Ni deposition on surface of the γ-alumina composite membrane led to hydrogen permeation via Knudsen diffusion combined with surface diffusion, which gave high H2 selectivity exceeding the Knudsen diffusion mechanism.
- Composite membrane
- Hydrogen separation
- Surface diffusion
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry