The adsorption and dissociation of water molecule on goethite (010) surface: A DFT approach

Zhang, Long; Xiu, Fangyuan; Qiu, Meng; Xia, Shuwei; Yu, Liangmin

doi:10.1016/j.apsusc.2016.09.038

Cited by 30 publications

(23 citation statements)

References 34 publications

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“…Despite experimental and theoretical work, there is still a need to understand the mechanism of steam‐enhanced carbonation because nearly all the proposed mechanisms are speculative. Recent studies show that the adsorption simulation using density functional theory (DFT) by first principles offers a fundamental way to explain the reaction mechanism . On one hand, the adsorption properties of CO 2 on different CaO surfaces have already been studied and the results showed that CO 2 molecules were strongly adsorbed on the O‐top site .…”

Section: Introductionmentioning

confidence: 99%

Explaining steam‐enhanced carbonation of CaO based on first principles

et al. 2018

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Calcium-based sorbents have been regarded as effective agents for capturing CO 2 from industrial flue gas. Recent studies have shown that steam can enhance the carbonation performance of calcium-based sorbents. In this paper, a CaO (001) surface was made to investigate the micro-level mechanism of steam-enhanced carbonation based on first principles calculations. Charge transfer and bond population were calculated to evaluate an interaction effect between adsorbates and the CaO (001) surface. Individual adsorption of CO 2 and H 2 O was compared with binary adsorption and co-adsorption of the two molecules on the CaO (001) surface, based on dispersion-corrected density functional theory (DFT-D) calculations. First, the predicted adsorption energies suggest the O-top site is the best site. It forms carbonate-like structure and hydroxyl-like structure for the individual adsorption of CO 2 and H 2 O. Binary adsorption calculations indicate that H 2 O is more easily adsorbed by the CaO (001) surface than CO 2 . The adsorption of H 2 O and CO 2 adsorption are promoted in comparison with their individual adsorption on the CaO (001) surface. Moreover, the analysis of adsorption energies and partial density of states (PDOS) suggests that a H 2 O-CaO (001) surface (CaO (001) surface that has already adsorbed H 2 O) is more reactive than the clean CaO (001) surface for CO 2 adsorption, which further supports the idea that the steam-enhanced mechanism is an Eley-Rideal (E-R) mechanism, which means H 2 O is adsorbed on the CaO surface, and then CO 2 is adsorbed. C

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Section: Introductionmentioning

confidence: 99%

Explaining steam‐enhanced carbonation of CaO based on first principles

et al. 2018

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“…3 × 3 × 1 Monkhorst‐Pack k‐point meshes were selected for all the calculations, while an energy tolerance of 2.0 × 10 −5 eV/atom, an SCF tolerance of 2.0 × 10 −6 eV/atom, a maximum force tolerance of 0.5 eV/nm, and a maximum displacement tolerance of 0.0002 nm were set, respectively. Considering that the OC surface directly participates in the redox reaction, which is more complicated than the bond formation or bond‐breaking between molecules or atoms, linear synchronous transit (LST)/optimization method 37 was used to perform a linear synchronous search for the transition state, which is a common interpolating geometrical method to find a reasonable reaction pathway between reactant and product 38 …”

Section: Methodsmentioning

confidence: 99%

Ammonia deep chemical looping combustion on perfect and reduced Fe ₂ O ₃ : A theoretical account

Luo

Feng

et al. 2021

Int J Energy Res

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Summary Chemical looping combustion (CLC) between Fe2O3 and NH3 can lead to the generation of H2O, H2, NO, and N2 as the main product under different reaction stages, reasonable control of which can realize effective conversion and utilization of NH3. To initiate the CLC reaction, NH3 is chemically adsorbed on the perfect Fe2O3 surface with a hybrid between N and Fe, leading to the dehydrogenation of NH3 into *NH2 as the first reaction step. Then the second dehydrogenation step (*NH2→*NH) acts as the speed‐control step for the oxidation of NH3 into H2O and N2, leading to the reduction of Fe2O3. The reduction of Fe2O3 promotes the further adsorption of NH3, especially the intermediate species *NH2, *NH, and *N, which favors the generation of H2O and N2. Further reduction of Fe2O3 into the oxidation state lower than ~Fe2O2.25 shows lower surface oxygen potential, which is beneficial to the formation of H2 and N2. Results suggest that reasonable control of the oxidation state of iron oxide can optimize the NH3 CLC process for H2 production.

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“…where E s is the energy of the slab model, N is the formula units contained in the slab, E bulk is the energy of the bulk cell, and A is the surface area of the slab. The surface energy of the hydrated surface model can be calculated as follows: 30,38…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Otte et al 29 found that the reactivity and adsorption configuration of water molecules were strongly dependent on the coordination structures of surface Fe atoms: water was chemisorbed at the fourfold-coordinated Fe2 site, whereas at the fivefoldcoordinated Fe1 site, water was only loosely bound with hydrogen pointing toward the surface. Zhou et al 30 systematically studied the adsorption morphology of water molecules on the goethite (010) surface at different coverages by DFT calculations, finding that water molecules could combine with the fourfold-coordinated Fe site to form a stable structure with sixfold coordination, and the water molecules spontaneously dissociated while completing the coordination shell of Fe sites on the goethite (010) surface under high coverage.…”

Section: ■ Introductionmentioning

confidence: 99%

Effects of the Goethite Surface Hydration Microstructure on the Adsorption of the Collectors Dodecylamine and Sodium Oleate

et al. 2021

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Dodecylamine (DDA) and sodium oleate (OL) are commonly used collectors in the reverse flotation and the direct flotation of goethite. However, the flotation mechanisms of DDA and OL on the goethite surface remain unclear. In this study, the first-principles density functional theory calculations were used to reveal the role of the hydration of the goethite surface and its effects on flotation reagents from a microscopic perspective. The calculation results showed that DDA was adsorbed on the surface of goethite by hydrogen bonds in the absence of hydration. However, the existence of the hydration microstructure hindered the formation of hydrogen bonds and made it difficult for DDA to be adsorbed on the goethite surface. In the OL system, oleate ions are chemically adsorbed on the surface Fe sites of goethite in the absence of hydration, while in the presence of hydration, the oleate ions were adsorbed on the H-terminal hydration surface of goethite by hydrogen bonds. This work sheds new light on the roles of the hydration microstructure and the adsorption mechanism of the flotation reagent on the oxide minerals.

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The adsorption and dissociation of water molecule on goethite (010) surface: A DFT approach

Cited by 30 publications

References 34 publications

Explaining steam‐enhanced carbonation of CaO based on first principles

Explaining steam‐enhanced carbonation of CaO based on first principles

Ammonia deep chemical looping combustion on perfect and reduced Fe ₂ O ₃ : A theoretical account

Effects of the Goethite Surface Hydration Microstructure on the Adsorption of the Collectors Dodecylamine and Sodium Oleate

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The adsorption and dissociation of water molecule on goethite (010) surface: A DFT approach

Cited by 30 publications

References 34 publications

Explaining steam‐enhanced carbonation of CaO based on first principles

Explaining steam‐enhanced carbonation of CaO based on first principles

Ammonia deep chemical looping combustion on perfect and reduced Fe 2 O 3 : A theoretical account

Effects of the Goethite Surface Hydration Microstructure on the Adsorption of the Collectors Dodecylamine and Sodium Oleate

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Ammonia deep chemical looping combustion on perfect and reduced Fe ₂ O ₃ : A theoretical account