Hydrogen and Nitrogen Permeability of Ni/PI laminated membrane

Abstract

When extracting hydrogen from ammonia, which is attracting attention as a new hydrogen carrier, it is necessary to extract only hydrogen from the hydrogen-nitrogen gas mixture. Hydrogen separation membranes are used as a means of gas separation, and high quality is required. In this study, focusing on the catalytic effect of transition metals, we fabricated metal/polymer multilayer membranes by layering transition metals on the surface of polyimide (PI) membranes with high heat resistance, and evaluated the hydrogen/nitrogen separation characteristics using the approach of measuring the permeability of the polymer membrane. The permeability coefficients of the Ni/PI multilayer films were measured using a gas permeability apparatus. The results showed that the Ni/PI laminate membrane exhibited a higher separation factor and a lower hydrogen permeation coefficient at low temperatures than the PI monolayer membrane, and these values became the same as those of the PI monolayer membrane as the temperature increased. This is because the Ni layer was the rate-limiting step in gas permeation at low temperatures, while the PI layer was the rate-limiting step at high temperatures.