Examinando por Materia "Mercury species"

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    PublicaciónAcceso abierto
    Adsorción de especies de mercurio sobre las superficies 1t-mno2 y 1t-mno2/grafeno
    (Universidad de Córdoba, 2022-08-18) Morinson Negrete, Juan David; Ortega López, César
    En esta tesis, se realizó un estudio de primeros principios de la adsorción de algunas especies de mercurio (Hg0 , HgCl, HgO y HgCl2) sobre una monocapa de 1T-MnO2 y una heteroestructura vertical de 1T-MnO2/Grafeno. Los cálculos se realizaron dentro del marco de la Teoría del Funcional de la Densidad (DFT). Inicialmente, se verificó la exactitud del método de cálculo, a través del análisis comparativo de algunas propiedades estructurales y electrónicas de la monocapa y la heteroestructura, con resultados previamente citados en la literatura. Asimismo, se examinó la estabilidad energética, mediante el cálculo de las energías de cohesión, formación y superficial (monocapa); y de manera análoga, del trabajo de separación y las energías de enlace, formación e interfacial (heteroestructura).
  • Miniatura
    PublicaciónAcceso abierto
    Adsorption of mercury species on the 1T-MnO2 and 1T-MnO2/Graphene surfaces
    (Universidad de Córdoba, 2022-08-13) Morinson Negrete, Juan David; Ortega López, César
    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.