A DFT study of Hg0 adsorption on Co3O4 (1 1 0) surface

Abstract

Spin polarized density functional theory calculation combined with periodic slabs were employed to reveal the elemental mercury (Hg 0) adsorption mechanism on Co 3 O 4 (1 1 0) surface. The adsorption energies and possible adsorption sites were investigated. To understand the adsorption interaction more directly, the electronic structural changes of before and after adsorption were compared. The hybridization of orbitals was studied by the partial density of states (PDOS) analysis. In addition, the temperature effects toward equilibrium constants of Hg 0-Co 3 O 4 system were taken into consideration. The results manifested that the interaction between Hg 0 and Co 3 O 4 (1 1 0) surface is chemisorption with-74.037kJ/mol. Co 3+ sites, the highest oxidation state of Co atoms, are crucial in this process which can accept the electrons after Hg oxidation. The redundant electrons transfer to O and other Co atoms nearby. PDOS analysis indicates the hybridization of s orbitals (Hg 0) and p, d orbitals (Co atom). And d orbitals of Hg interacts with s, p orbitals of Co atom strongly. The trends of equilibrium constants suggest that Hg 0 adsorption on Co 3 O 4 (1 1 0) surface is favorable at low temperature.

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