DFT studies of adsorption properties and bond strengths of H2S, HCN and NH3 on Fe(1 0 0)

Ren, Longfang; Cheng, Yanhai; Shao, Rui; Meng, Xiuxia; Yang, Jinyong; Wang, Qingqing

doi:10.1016/j.apsusc.2019.144232

Cited by 46 publications

(16 citation statements)

References 42 publications

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“…Insights have been gained from frontier molecular orbitals, adsorption isosteric heat, and bond lengths . Possible active sites and intermolecular interactions could be predicted by the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) through accepting or donating electrons based on density functional theory (DFT), which have been successfully applied to analyze interactions between organo-SiNPs and tritoluene dyes (malachite green, crystal violet, and bromophenol blue) . To date, theoretical investigations about the modification of organo-SiNPs are limited at hexadecyl trimethyl ammonium bromide and hexadecyl trimethoxysilane, which are seldomly extended to the modification and simulation about organic modification of SiNPs by functional gemini surfactants …”

Section: Introductionmentioning

confidence: 99%

Effective Adsorption of Methyl Orange on Organo-Silica Nanoparticles Functionalized by a Multi-Hydroxyl-Containing Gemini Surfactant: A Joint Experimental and Theoretical Study

et al. 2021

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A novel multi-hydroxyl-containing gemini surfactant (G16) is first designed for modifying silica precursors (SiNPs), with the purpose of fabricating organic adsorbents targeted at methyl orange (MO). The purity of G16 and structural character of the resultant G16-SiNPs are unveiled through Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry-derivative thermogravimetry, scanning electron microscopy, and surface analysis (BET). Compared with SiNPs, G16-SiNPs exhibit enhanced hydrophobicity, enlarged interlayer spacing, and increased thermal weight losses with the modifier availability reaching as high as 100%. Enhanced MO adsorption is obtained from the higher adsorption capacity of G16-SiNPs (401.88 mg/g) than SiNPs (64.72 mg/g), which is more effective than most of the existing silica-based adsorbents. Pseudo-second-order and Langmuir models conform to all adsorption processes, indicating that the adsorption mainly relies on the availability of adsorption sites and characterized by a homogeneous adsorption form. By combining the experimental study and theoretical calculation methods, it can be demonstrated that the as-synthesized adsorbent G16-SiNPs own multi-active sites that contribute to multi-adsorption mechanisms. The partition process, electrostatic interactions, and OH−π interactions are all responsible for the adsorption performance of G16-SiNPs. This study throws light on the exploration of the superb MO adsorbent in aspects of not only the novel structured modifier and precursor but also theoretical analysis for gaining insights into the adsorption mechanism.

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Section: Introductionmentioning

confidence: 99%

Effective Adsorption of Methyl Orange on Organo-Silica Nanoparticles Functionalized by a Multi-Hydroxyl-Containing Gemini Surfactant: A Joint Experimental and Theoretical Study

et al. 2021

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“…As shown in Figure 3, the calculated E ads for NH 3 adsorption on Fe 2 O 3 , Fe 2 O 2.5 , Fe 2 O 2.25 , Fe 2 O 2 , Fe 2 O 1.75 , and Fe is −1.23 eV (close to the results of Zhu et al with the E ads of −1.22 eV and Fang et al), 39,40 −1.28, −1.29, −1.31, −1.29, and −1.22 eV, respectively. E ads of −1.22 eV for the NH 3 ‐Fe adsorption system is higher than −0.98 eV for NH 3 adsorption on Fe(100), 41 since the reduced Fe surface from Fe 2 O 3 shows more structural defects and hence higher activity than the perfect Fe(100). With the reduction of Fe 2 O 3 , the non‐stoichiometric specific surface, especially around Fe 2 O 1.75 , is more conducive to the adsorption of NH 3 .…”

Section: Resultsmentioning

confidence: 86%

“…For the third DeH step, *NH can either decompose into *N and *H, or into *N and H 2 O, but the E a for *NH → *N + *H is far lower than for *NH + OH → *N + H 2 O. In comparison with the reaction enthalpy for the DeH reaction of the pure NH 3 , NH 2 , and NH (4.7, 4.0, and 3.4 eV, respectively), 41 it could be observed that Fe 2 O 3 can obviously reduce the reaction enthalpy for the gradual DeH of NH 3 into NH 2 , NH, and N during the CLC process. The first and second DeH steps are endothermic while the third step is exothermic 42,43 .…”

Section: Resultsmentioning

confidence: 92%

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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“…The interaction between nucleus and electron is treated by ultra-soft pseudopotential. The generalized gradient approximation (GGA) parameterized by Perdew-Burke-Ernzerh (PBE) is used to describe the exchange correlation energy, and the plane wave basis set is used to expand the wave function [26][27][28], and the truncation energy is 450eV.…”

Section: Methodsmentioning

confidence: 99%

DFT study of the fouling deposition process in the steam generator by simulating the absorption of Fe2+ on Fe3O4 (001) 

Pan¹,

Lu²,

Xu³

et al. 2021

Preprint

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In this paper, the interaction between free Fe2+ and Fe3O4 corrosion products on the pipe surface in the secondary circuit of PWR nuclear power plant was studied, and the reason of agglomeration formation was analyzed. The complex physical and chemical interaction was simplified by describing the electron interaction. Based on the first principles, CASTEP was used to simulate seven kinds of highly symmetric adsorption structure models of Fetet1 and Feoct1 on Fe3O4 (001) surface, and their adsorption energies and stable adsorption conformations were calculated. The results show that the most stable adsorption structures of the Fe2+/Fe3O4 (001) configurations are Feoct1-b and Fetet1-Oh. During the adsorption, the Fe-Fe, Fe-O bond length and Fe-Fe-O bond angle of (001) surface changed, and the atomic positions parallel and perpendicular to (001) surface changed correspondingly, the surface layer changes the most. The results prove that the adsorption has great effect on the physical structure of Fe2+ and Fe3O4 (001). The calculation of charge population, the density of states and electron local function of Fe2+/Fe3O4 (001) optimal adsorption configuration also shows that there is electron transfer between Fe2+ and Fe3O4 (001), and the adsorption type is chemisorption. Among them, Fe (Fe2+)-Fe (Fe3O4) forms a metal bond, and Fe (Fe2+)-O (Fe3O4) forms the ionic bond.

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DFT studies of adsorption properties and bond strengths of H2S, HCN and NH3 on Fe(1 0 0)

Cited by 46 publications

References 42 publications

Effective Adsorption of Methyl Orange on Organo-Silica Nanoparticles Functionalized by a Multi-Hydroxyl-Containing Gemini Surfactant: A Joint Experimental and Theoretical Study

Effective Adsorption of Methyl Orange on Organo-Silica Nanoparticles Functionalized by a Multi-Hydroxyl-Containing Gemini Surfactant: A Joint Experimental and Theoretical Study

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

DFT study of the fouling deposition process in the steam generator by simulating the absorption of Fe2+ on Fe3O4 (001)

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DFT studies of adsorption properties and bond strengths of H2S, HCN and NH3 on Fe(1 0 0)

Cited by 46 publications

References 42 publications

Effective Adsorption of Methyl Orange on Organo-Silica Nanoparticles Functionalized by a Multi-Hydroxyl-Containing Gemini Surfactant: A Joint Experimental and Theoretical Study

Effective Adsorption of Methyl Orange on Organo-Silica Nanoparticles Functionalized by a Multi-Hydroxyl-Containing Gemini Surfactant: A Joint Experimental and Theoretical Study

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

DFT study of the fouling deposition process in the steam generator by simulating the absorption of Fe2+ on Fe3O4 (001)&nbsp;

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DFT studies of adsorption properties and bond strengths of H2S, HCN and NH3 on Fe(1 0 0)

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

DFT study of the fouling deposition process in the steam generator by simulating the absorption of Fe2+ on Fe3O4 (001)