The structure and dipolar properties of CO2 adsorbed in a porous glassy chalcogel: Insights from first-principles molecular dynamics

A thorough understanding of the interactions of CO2 with the hosting porous network is crucial for the design of new adsorbent materials with enhanced gas adsorption capacity and selectivity. In this paper, first-principles molecular dynamics simulations are performed to assess the interactions of CO2 adsorbed in a nanoporous glassy chalcogenide (i.e. chalcogel) under relevant laboratory conditions. The structure and local organization of the confined CO2 molecules are analyzed in terms of atomic density, orientational order parameter and pair correlation functions. Maximally localized Wannier functions are used to unravel the electronic structure, the local molecular dipole and the nature of the chemical bonding at the interface between CO2 and the glassy surface. Our results provide a useful insight on the complex interplay between the chemical interactions competing at the buried interface made by the CO2 molecules adsorbed in g-GeS2 chalcogel.