The effect of nitrogen doping on mercury oxidation/chemical adsorption on the CuCo₂O₄(110) surface: a molecular-level description

Abstract

Based on density functional theory (DFT) calculations, the detailed mercury oxidation/chemical adsorption mechanisms on the N-doped CuCo2O4(110) surface are studied. The DFT calculations show that Ow (bonded with one Cu(2+) ion and one Co(3+) ion) is far more active than Os (bonded with three Co(3+) ions) and the mercury oxidation/chemical adsorption activation energy (Ea) on the virgin CuCo2O4(110) surface involving Ow is 0.85 eV. The physically adsorbed mercury overcomes the Ea and enters the energy well that plays an important role in mercury oxidation/chemical adsorption. Nitrogen doping can greatly increase the activity of Ow and decrease the activity of Os at the same time, which greatly affect the mercury oxidation/chemical adsorption abilities on the CuCo2O4(110) surface, and the Ea variation of mercury oxidation/chemical adsorption is as follows: 0.85 eV (virgin CuCo2O4(110)) → 0.76 eV (one N-doped CuCo2O4(110)) → 0.69 eV (two N-doped CuCo2O4(110)) → 0.48 eV (three N-doped CuCo2O4(110)). In addition, N-doping can decrease the adsorption energy of mercury and mercuric oxide. The effect of N-doping on the bonding mechanism of mercury adsorption on the CuCo2O4(110) surface is analyzed by the local density of state (LDOS) and the natural bonding orbital (NBO). The calculation results correspond well to the experimental data.

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

“…In previous DFT studies, GGA-PBE method was employed in Mn or Co elements contained metal oxidize system which showed reasonable accuracy [23,29]. This method also had good performance in bulk CoMnO 3 .…”

Application of computational chemistry in understanding the mechanisms of mercury removal technologies: a review

“…In addition, the SO 2 anti-poisoning ability of Cu x Co 3Àx O 4 increased with a (110) slab is the top view, and the below is the side view. 38 continuous increase of x from 0.75 to 2.25. Therefore, the periodic CuCo 2 O 4 (110) surface using the four-layer and p(2 Â 2) model has been built (Fig.…”

“…All calculations were performed in CASTEP with the GGA-PBE functional. 38 In fact, DFT + U should be used in this strongly correlated material. The mercury oxidation/chemical adsorption on these surfaces is studied.…”

“…We have also done some previous work in this field. [36][37][38] The nature of adsorption and oxidation of mercury has been established. Although some reviews focusing on mercury removal technologies including the preparation, activity and stability of catalysts have been reported, [20][21][22] a critical review of the recent advances in the application of theoretical calculation methods for understanding mercury removal mechanisms in flue gas is lacking.…”

“…28 The notation of atoms in the CuCo 2 O 4 (110) slab and the illustration of two orientations of the CuCo 2 O 4 (110) slab. The upper CuCo 2 O 4(110) slab is the top view, and the below is the side view 38.…”