First principles study of elemental mercury (Hg0) adsorption on low index CoMnO3 surfaces

Abstract

The density functional theory (DFT) is applied to predict elemental mercury (Hg 0) adsorption on CoMnO 3 surface for the first time. GGA/PBE functional were selected to determine the potential Hg 0 capture mechanisms. The results show that Hg 0 has good affinity with CoMnO 3 surfaces with chemical adsorption. The adsorption energy of Hg 0-CoMnO 3 (1 0 0), Hg 0-CoMnO 3 (1 0 1) and Hg 0-CoMnO 3 (1 1 0) are-85.225,-72.305 and-70.729 kJ/mol, respectively. The Hg-Mn and Hg-Co mechanisms were revealed on low index surfaces. Hg 0 was oxidized to its valence state of 0.236 on Mn site in CoMnO 3 (1 0 0) surface. The Hg-Co interaction mechanism occurred on Hg 0-CoMnO 3 (1 0 1) and Hg 0-CoMnO 3 (1 1 0) with 0.209eand 0.189etransformation, respectively. The PDOS analysis shows that Hg-Mn interaction depends on the hybridization of Hg(s-and d-orbitals) and Mn (s-, p-and d-orbitals). However, Hg-Co interaction stems from sand d-orbitals of Hg, which only overlapping with d-and p-orbital of Co. Both the adsorption energy and electronic structure analysis indicated that CoMnO 3 catalyst performed excellent in Hg 0 oxidation. Exposing CoMnO 3 (1 0 0) is most favorable in Hg 0 control, which provides theoretical instruction on certain crystal plane synthesis in experiment.

Unveiling Adsorption Mechanisms of Elemental Mercury on Defective Boron Nitride Monolayer: A Computational Study

“…10−13 However, the costs of these metals as sorbents are still very high. Hence, many reports have also shown that low-cost transition metal oxides (e.g., Co 3 O 4 , 14 ZnO, 15 MnO 2 , 16−20 Fe 2 O 3 , 21 CuO, 22 CoMnO 3 , 23 and CaO 24,25 ) and spinel ferrite 26 are suitable materials for the removal of Hg 0 . To date, novel sorbent injection is still considered to be a potential and cost-effective mercury removal technology.…”

Molecular Mechanistic Nature of Elemental Mercury Oxidation by Surface Oxygens over the Co3O4 Catalyst

“…The corresponding adsorption energies are −0.57 and −0.61 eV, respectively, which are less than those of 1C. Additionally, many other studies ,,, also found that the surface metal sites are more active than oxygen sites for Hg 0 adsorption. All of the above analyses suggest that Hg 0 adsorption on the Co 3 O 4 catalyst is controlled by the chemisorption mechanism and the surface Co 3+ is the most active adsorption site.…”

“…Fortunately, density functional theory (DFT) calculations can be used to fill this gap. Increasingly, researchers have performed DFT calculations to study Hg 0 adsorption and oxidation on different sorbents − and catalysts − at the molecular level.…”

Fundamental Mechanisms of Mercury Removal by FeCl3- and CuCl2-Impregnated Activated Carbons: Experimental and First-Principles Study

“…DFT calculations have provided powerful support for experimental studies on mercury chemistry through the analysis of adsorption energies, electronic geometry, charge transfer, thermodynamic properties, etc. Researchers have reported the adsorption and oxidation mechanisms of mercury species on various metals, − metal oxides, − carbonaceous surfaces, − CaO surfaces, spinel-type MnFe 2 O 4 , perovskite-type CoMnO 3 surfaces, metal sulfide surfaces, metal--organic frameworks (MOFs), and alkali-metal-based sorbents using theoretical methods. Theoretical calculations have also been carried out to elucidate the mechanism of mercury oxidation over chlorine- and cupric-impregnated activated carbon , and on single-atom catalysts with different graphene-based substrates …”

“…11,18−20 Quantum chemical calculations, especially density functional theory (DFT), are ideally suited for evaluating heterogeneous oxidation mechanisms involved in mercury species adsorption on sorbent/catalyst surfaces at the molecular-electronic level. 41 surfaces, metal sulfide surfaces, 42 metal--organic frameworks (MOFs), 43 and alkali-metal-based sorbents 44 using theoretical methods. Theoretical calculations have also been carried out to elucidate the mechanism of mercury oxidation over chlorine-and cupric-impregnated activated carbon 45,46 and on single-atom catalysts with different graphene-based substrates.…”