Using first-principles calculations to accelerate materials discovery for hydrogen purification membranes by modeling amorphous metals

Abstract

Efficient purification of hydrogen from high temperature mixed gas streams can potentially play a critical role in the large-scale production of hydrogen from gasification of coal or biomass. Dense metal membranes have many favorable properties for this kind of purification, but existing membranes based on crystalline metal alloys have a number of limitations. The use of amorphous metal films as membranes has potential to overcome at least some of the disadvantages of crystalline metal membranes. We present new modeling methods that make it possible for the first time to quantitatively predict the performance of amorphous metal films as hydrogen purification membranes. These methods are introduced by examining amorphous Fe₃B, a material where comparisons can be made to a crystalline material with the same composition. A membrane made from the amorphous material is predicted to have a hydrogen permeability 1.5–2 orders of magnitude higher than a crystalline membrane. The methods we introduce here will be useful in accelerating the development of amorphous membranes for practical applications.