How Surface Reconstruction Affects Hydrogen Dissociation on the N-Precovered W(110): A Theoretical Perspective

We make use of density functional theory and ab initio molecular dynamics to elucidate, at the atomic scale, the impact of adsorbed nitrogen (N) impurities on W(110) surface on H₂ dissociative chemisorption. Our primary focus is on a nitrogen coverage of 0.25 monolayer (ML), for which two surface structures have been postulated previously in the literature. The first structure involves N adsorption on the surface, while the second involves N absorption between the first two tungsten layers. The present study demonstrates that dissociative chemisorption of hydrogen is critically sensitive to the surface structure. The sublayer absorption of nitrogen involves a surface reconstruction that renders one displaced W atom highly reactive in terms of H₂ dissociation. The dynamics are analyzed in view of previous results on clean and O-precovered W(110) surfaces.