(785a) Quantitative Computational Screening of Pd-Based Intermetallic Membranes for Hydrogen Separation

Intermetallics are stoichiometric compounds of two or more metals, which are known to exhibit structural and physical properties often different from their constituent elements. In this work, 78 Pd-based binary intermetallic membranes were screened for hydrogen separation from gas mixtures. A systematic computational screening approach based on calculation of key properties like solubility, diffusivity and permeability of hydrogen through these materials was developed.  No Pd-based intermetallic was found to have favorable hydrogen permeabilities for separation applications. The hydrogen solubility of different metastable structures of the same intermetallic was studied to understand the impact of structure on the hydrogen binding energy. Pd₃Mn was chosen since it is structure, hydrogen binding energy and activation barrier for diffusion was found to be similar to pure Pd. Different structures of the same intermetallic were found to have different hydrogen binding energy. Hydrogen stabilizes two Pd₃Mn metastable phases. These metastable phases are predicted to have favorable solubilities at very low hydrogen pressures. Our calculations provide a useful method for analyzing a large set of materials from first principles and shortlisting materials that show properties useful for applications such as hydrogen separation.