Progressive Dehydrogenation of LiNH ₂ Materials on Ru(0001) Based on <i>ab initio</i> Interface Models

ABSTRACT Density Functional Theory calculations were performed to design atomistic models of ruthenium surfaces interfaced with partially dehydrogenated lithium‐based layers (LiNH 2 , Li 2 NH, and Li 3 N). The structural, energetic, and magnetic properties of Li 2 NH and Li 3 N bulks and surfaces were systematically evaluated by using the GGA–PBE and dispersion‐corrected PBE–dDsC functionals. The surface‐termination analysis showed that the (100) orientations of these compounds minimize the lattice mismatch with Ru(0001), favoring interface formation. Based on these results, a multilayer model, Ru(0001)/Li 3 N(001)/Li 2 NH(001)/LiNH 2 (001), was developed to describe the progressive dehydrogenation of LiNH 2 in contact with Ru. The partially dehydrogenated interface showed a greater thermodynamic stability than fully hydrogenated systems. Energetic and magnetic analyses indicated that progressive dehydrogenation enhances interfacial stability, allowing the suggestion of mechanistic assumptions for ammonia decomposition. Overall, this study offers an atomistic perspective on Li–N–H/Ru interfaces and a basis for designing improved catalysts for ammonia decomposition and hydrogen storage.