Existence of the Na−H^δ-···H^δ‘+−O Dihydrogen Bond in the Hydrogenation Process by Na₂O:  A First-Principles Identification

Abstract

The adsorption and dissociation of H2 on the Na2O (110) surface have been studied with the first-principles molecular dynamics method. It is found that the adsorption configuration is energetically preferred when the H2 molecule is situated at the bridge site of the Na and O atoms, which indicates the formation of a Na−Hδ-···Hδ‘+−O dihydrogen bond, as confirmed by the charge distribution features and bond lengths between the concerned atoms. The molecular dynamics simulations reveal the dissociation of the newly discovered H···H dihydrogen bond, which facilitates the Na2O + H2 → NaH + NaOH reaction.

Dehydrogenation Reaction for NaOH System: A First‐Principles Study

“…In our previous paper, we addressed the existence of a dihydrogen bond and its role during the process of hydrogenation of Na 2 O. [10] Herein, it is of particular interest to understand the lattice dynamics of the NaÀOÀH system, including Na 2 O, NaH, NaOH and H 2 . The vibrational properties such as the phonon dispersion relations and phonon density of states (PDOS) are calculated based on a direct force-constant method, and then the thermodynamic functions are derived within the quasiharmonic approximation (QHA).…”