Resumen en inglés

The most relevant results are shown in this thesis report. In this thesis a first-principles study of the adsorption of some mercury species (HgCl and HgO) on the 1T- MnO2/Graphene heterostructure was carried out. Calculations were performed using the Density Functional Theory (DFT) within the framework of Generalized Gradient Approximation of Perdew-Burke and Ernzerhof (GGA-PBE) along with ultrasoft atomic pseudopotentials. In this investigation, the surface of interest is the monolayer of 1T-MnO2 coupled to a monolayer of Graphene and its interaction with the mercury species. The Graphene monolayer only acts as a substrate to support the 1T-MnO2 monolayer; for that reason, in all of the processes of adsorption of the mercury species onto the heterostructure, the atomic positions of the Graphene remain fixed. In order to establish the most energetically stable adsorption configurations, the following special sites on the heterostructure were considered: TO1 (top O atom of the lower horizontal plane), TO2 (top O atom of the upper horizontal plane), TM1 (top Mn atom located above a C atom) and TM2 (top Mn atom located above of the center of a Graphene hexagon), B1 (top bridge Mn-O1) and B2 (top bridge Mn-O2). In addition, for the molecurlar species (HgCl and HgO), different initial orientations (⊥, ∥ and ∡) with respect to the horizontal planes of the heterostructure were considered. It was found that the most stable adsorption configurations corresponds to: HgCl: chemisorbed molecule (Eads=−1.668 eV) perpendicularly with the Hg atom closest to the heterostructure in TO2. HgO: chemisorbed molecule (Eads=−1.904 eV) perpendicularly with the Hg atom closest to the heterostructure in TO2. Finally, the results obtained show that the 1T-MnO2/Graphene heterostructure is theoretically good-adsorbent material for the analyzed mercury species.