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.
Copyright 2009 Elsevier B.V., All rights reserved.
- Composite membrane
- Hydrogen separation
- Surface diffusion
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry