First-principles investigations into the effect of oxygen vacancies on the enhanced reactivity of NiO via Bader charge and density of states analysis

Rasi, Negar Manafi; Ponnurangam, Sathish; Mahinpey, Nader

doi:10.1016/j.cattod.2022.01.012

Cited by 30 publications

(8 citation statements)

References 30 publications

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“…Bader charge analysis reveals that the charges of both Cu and Mn ions near the oxygen vacancy notably increase, indicating electron enrichment around these ions (Figure e). This enrichment leads to reduced valence states of Cu and Mn ions induced by the oxygen-deficient surface . For comparative analysis, we conducted Bader charge analyses on CuO and Mn 2 O 3 surfaces using stable CuO(111) (refer to Figure S8) and Mn 2 O 3 (111) (see Figures S9 and S10) crystal planes. , …”

Section: Resultsmentioning

confidence: 99%

“…This enrichment leads to reduced valence states of Cu and Mn ions induced by the oxygen-deficient surface. 48 For comparative analysis, we conducted Bader charge analyses on CuO and Mn 2 O 3 surfaces using stable CuO(111) (refer to Figure S8) and Mn 2 O 3 (111) (see Figures S9 and S10) crystal planes. 34,49 The Bader charges of the CuO(111) surface before and after the oxygen vacancy are shown in Figure 2f.…”

Section: ■ Introductionmentioning

confidence: 99%

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Construction of Surface Synergetic Oxygen Vacancies on CuMn₂O₄ Spinel for Enhancing NO Reduction with CO

Xu,

Liu,

et al. 2024

ACS Catal.

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The effectiveness of surface synergetic oxygen vacancy (SSOV) on a catalyst has been proposed in the selective reduction of NO to N2 by CO. In this work, we prepared fresh CuMn2O4 spinel catalyst using the freeze-assisted sol–gel method, and then engineered SSOVs through CO pretreatment (CO–CuMn2O4) at 250 °C. The catalytic performance of the CO–CuMn2O4 catalyst showed significant improvement, attributed to the presence of SSOVs, in comparison to that of the fresh CuMn2O4 sample. Additionally, our findings elucidated the limited reactivity of surface oxygen vacancies (SOVs) on a single metal oxide, emphasizing the crucial role played by SSOVs. Experimental results, including NO temperature-programmed desorption-mass spectrometry and in situ diffuse reflectance infrared Fourier transform spectroscopy, provided further insights by suggesting that SSOVs facilitate the formation of N2O and its subsequent decomposition into N2. Density functional theory calculations have unveiled the pivotal role of SSOV in stabilizing the nitrogen atom derived from gaseous NO, facilitating the NO + CO → N* + CO2 reaction. Notably, the energy barrier for this process is only 0.54 eV, which is the rate-determining step of the NO + CO reaction. In stark contrast, this reaction scarcely occurs on the SOVs of single CuO and Mn2O3 surfaces. Furthermore, the presence of SSOVs considerably lowers the energy barrier for the conversion of N2O to N2, with a minimal barrier of 0.12 eV. In contrast, the reduction of N2O by CO without SSOV assistance necessitates a significantly higher energy barrier of 2.77 eV. Extending our investigation, we engineered SSOVs on the CuFe2O4 spinel catalyst and observed similar SSOV-mediated effects in the NO + CO reaction. Our research offers a comprehensive understanding of atomic-level role of SSOV, thereby offering valuable insights for the design of efficient NO + CO catalysts.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Construction of Surface Synergetic Oxygen Vacancies on CuMn₂O₄ Spinel for Enhancing NO Reduction with CO

Xu,

Liu,

et al. 2024

ACS Catal.

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“…Figure shows the first-principles simulation results for hydrogen-penetrated Er 2 O 3 , and the crystal structure is depicted in Figure a. The Bader charge was used to analyze the electron transfer in the H-Er 2 O 3 simulation. , The electrostatic charge of each atom is shown in Figure b. During bonding, the hydrogen atom gained 0.35 eV, and correspondingly, the connected O36 atom lost 0.35 eV, indicating that the electrons lost by the O atom were exactly transferred to the H atom, which weakened the bond between the O and surrounding Er atoms.…”

Section: Resultsmentioning

confidence: 99%

Effects of Internal Stress and Hydrogen Penetration on the Performance of Er₂O₃ Coatings as Hydrogen Permeation Barriers

Zheng,

Yang,

Yan

et al. 2024

ACS Appl. Mater. Interfaces

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Ceramic coatings that can effectively prevent hydrogen permeation have a wide range of applications in hydrogen energy and nuclear fusion reactors. In this study, for the first time, the internal stress of Er 2 O 3 coatings was found to be a key factor that could determine their hydrogen permeation resistance and lifespan. The internal stress was controlled by designing layered Er 2 O 3 coatings. The internal stress increased with an increasing number of Er 2 O 3 layers. When the number of layers was below 15, the increased internal stress did not adversely affect the coating performance and might help to increase its hydrogen permeation resistance. Although the overall thickness of the 15-layer Er 2 O 3 coating was only 97 nm, its hydrogen permeation reduction factor (PRF) reached the highest value of 626, whereas a further increase in the internal stress detrimentally affected the ability of the coating to reduce hydrogen permeation. In addition, the experimental observations and simulation results revealed that the performance of the Er 2 O 3 coatings was related to the hydrogen atoms that penetrated the coating, which weakened the Er−O bonds and consequently decreased the Er 2 O 3 fracture limit. This study provides insights into the effects of internal stress and hydrogen penetration on the performance of ceramic coatings as hydrogen permeation barriers and will help guide strategies for the structure design of hydrogen permeation barriers possessing high PRFs and long lifespans.

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“…This showed that TCEB could transfer more electrons to form the coordination bond with the Co atom on the electrode surface during the cathode electrode moving out of Li + . The Bader charge analysis is an intuitive method to analyze an atom based on electron charge density − which can quantify the charge distribution on the adsorbent surface . The Bader charge of the Co atom on the LiCoO 2 surface was 7.69, and the Bader charges of the Co atom on the LiCoO 2 –EC and LiCoO 2 –TMB surfaces were 7.53 and 7.54, respectively.…”

Section: Resultsmentioning

confidence: 99%

Structure Property and Reaction Mechanism of Boron-Based High-Voltage Electrolyte Additives via First-Principles Calculations

Song

Mao

et al. 2023

ACS Appl. Energy Mater.

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Boron-based additives are currently the mainstream filmforming additives. They generate B−F-containing species and then participate in the formation of the cathode−electrolyte interphase (CEI) film. However, little is known about their oxidative decomposition mechanisms, reaction processes, and the relationship between their molecular structure and interface stability in electrolyte. Here, the reaction mechanisms and processes of trimethyl borate (TMB) with fluorides (F − , PF 6 − , HF, and PF 5 ) in electrolyte were calculated and studied by combining theoretical and experimental methods. TMB was found to be capable of reacting with fluorides and self-dimerize in a nucleophilic manner. In addition, a comparative study was performed with tris(2-cyanoethyl) borate (TCEB), structurally similar to TMB. TMB and TCEB had the same reaction sites and almost the same energy barriers, and they participated in similar reaction processes. The decomposition of boron-based additives was analyzed through simulations and experiments to fill the gap in the information on the reaction mechanisms and processes of boron-based additives. This work also explored the influence of molecular structure on the mechanism of film formation, thus providing theoretical guidance for the molecular structure design of high-pressure additives and offering ideas for developing electrolyte additives.

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First-principles investigations into the effect of oxygen vacancies on the enhanced reactivity of NiO via Bader charge and density of states analysis

Cited by 30 publications

References 30 publications

Construction of Surface Synergetic Oxygen Vacancies on CuMn₂O₄ Spinel for Enhancing NO Reduction with CO

Construction of Surface Synergetic Oxygen Vacancies on CuMn₂O₄ Spinel for Enhancing NO Reduction with CO

Effects of Internal Stress and Hydrogen Penetration on the Performance of Er₂O₃ Coatings as Hydrogen Permeation Barriers

Structure Property and Reaction Mechanism of Boron-Based High-Voltage Electrolyte Additives via First-Principles Calculations

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First-principles investigations into the effect of oxygen vacancies on the enhanced reactivity of NiO via Bader charge and density of states analysis

Cited by 30 publications

References 30 publications

Construction of Surface Synergetic Oxygen Vacancies on CuMn2O4 Spinel for Enhancing NO Reduction with CO

Construction of Surface Synergetic Oxygen Vacancies on CuMn2O4 Spinel for Enhancing NO Reduction with CO

Effects of Internal Stress and Hydrogen Penetration on the Performance of Er2O3 Coatings as Hydrogen Permeation Barriers

Structure Property and Reaction Mechanism of Boron-Based High-Voltage Electrolyte Additives via First-Principles Calculations

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Construction of Surface Synergetic Oxygen Vacancies on CuMn₂O₄ Spinel for Enhancing NO Reduction with CO

Construction of Surface Synergetic Oxygen Vacancies on CuMn₂O₄ Spinel for Enhancing NO Reduction with CO

Effects of Internal Stress and Hydrogen Penetration on the Performance of Er₂O₃ Coatings as Hydrogen Permeation Barriers