scholarly journals Investigation of the dissolution and diffusion properties of interstitial oxygen at grain boundaries in body-centered-cubic iron by the first-principles study

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8643-8653
Author(s):  
Zhijie Liu ◽  
Yange Zhang ◽  
Xiangyan Li ◽  
Yichun Xu ◽  
Xuebang Wu ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
First Principles ◽  
Energy Barrier ◽  
High Energy ◽  
Low Energy ◽  
Interstitial Oxygen ◽  
Body Centered Cubic ◽  
High Energy Barrier ◽  
And Diffusion ◽  
Diffusion Properties

Oxygen atoms prefer to segregate to grain boundaries (2/2′). They segregate to Σ3〈110〉(111) with low energy barrier, but concentrate at the transition region of Σ5〈001〉(310) due to high energy barrier. They diffuse in grain boundaries (3/3′) more than in bulk (1/1′).

Enhancing the energy barrier and hysteresis temperature in two benchtop-stable Ho(III) single-ion magnets

2021 ◽  
Author(s):  
Kexin Jia ◽  
Xixi Meng ◽  
Mengmeng Wang ◽  
Xiaoshuang Gou ◽  
Yu-Xia Wang ◽  
...  
Keyword(s):  
Energy Barrier ◽  
High Energy ◽  
Halogen Anion ◽  
High Energy Barrier

The energy barrier and hysteresis temperature in two benchtop-stable D5h-symmetry HoIII single-ion magnets were significantly enhanced via the variation of halogen anion. The coexistence of high energy barrier of 418...

scholarly journals Insights on forming N,O-coordinated Cu single-atom catalysts for electrochemical reduction CO2 to methane

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanming Cai ◽  
Jiaju Fu ◽  
Yang Zhou ◽  
Yu-Chung Chang ◽  
Qianhao Min ◽  
...  
Keyword(s):  
Energy Barrier ◽  
Active Sites ◽  
Theoretical Calculations ◽  
High Energy ◽  
Single Atom ◽  
Faradaic Efficiency ◽  
High Energy Barrier ◽  
Catalytic Sites ◽  
Electron Reduction ◽  
First Time

AbstractSingle-atom catalysts (SACs) are promising candidates to catalyze electrochemical CO2 reduction (ECR) due to maximized atomic utilization. However, products are usually limited to CO instead of hydrocarbons or oxygenates due to unfavorable high energy barrier for further electron transfer on synthesized single atom catalytic sites. Here we report a novel partial-carbonization strategy to modify the electronic structures of center atoms on SACs for lowering the overall endothermic energy of key intermediates. A carbon-dots-based SAC margined with unique CuN2O2 sites was synthesized for the first time. The introduction of oxygen ligands brings remarkably high Faradaic efficiency (78%) and selectivity (99% of ECR products) for electrochemical converting CO2 to CH4 with current density of 40 mA·cm-2 in aqueous electrolytes, surpassing most reported SACs which stop at two-electron reduction. Theoretical calculations further revealed that the high selectivity and activity on CuN2O2 active sites are due to the proper elevated CH4 and H2 energy barrier and fine-tuned electronic structure of Cu active sites.

Slow magnetic relaxation in dinuclear dysprosium and holmium phenoxide bridged complexes: a Dy2 single molecule magnet with a high energy barrier

2021 ◽  
Author(s):  
Matilde Fondo ◽  
Julio Corredoira-Vázquez ◽  
Ana M. Garcia-Deibe ◽  
Jesus Sanmartin Matalobos ◽  
Silvia Gómez-Coca ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Single Molecule ◽  
Energy Barrier ◽  
Magnetic Relaxation ◽  
High Energy ◽  
Single Molecule Magnet ◽  
High Energy Barrier ◽  
Slow Magnetic Relaxation

Dinuclear [M(H3L1,2,4)]2 (M = Dy, Dy2; M = Ho, Ho2) complexes were isolated from an heptadentate aminophenol ligand. The crystal structures of Dy2·2THF, and the pyridine adducts Dy2·2Py and Ho2·2Py,...

First principle simulation on oxidation mechanism of diethyl ether by nitrogen dioxide

2015 ◽  
Vol 14 (03) ◽  
pp. 1550020 ◽  
Author(s):  
Yuan Yuan ◽  
Wei Hu ◽  
Xuhui Chi ◽  
Cuihua Li ◽  
Dayong Gui ◽  
...  
Keyword(s):  
Diethyl Ether ◽  
Energy Barrier ◽  
Density Functional ◽  
Oxidation Process ◽  
Oxidation Mechanism ◽  
High Energy ◽  
First Principle ◽  
Functional Theory ◽  
The Third ◽  
High Energy Barrier

The oxidation mechanism of diethyl ethers by NO2was carried out using density functional theory (DFT) at the B3LYP/6-31+G (d, p) level. The oxidation process of ether follows four steps. First, the diethyl ether reacts with NO2to produce HNO2and diethyl ether radical with an energy barrier of 20.62 kcal ⋅ mol-1. Then, the diethyl ether radical formed in the first step directly combines with NO2to form CH3CH ( ONO ) OCH2CH3. In the third step, the CH3CH ( ONO ) OCH2CH3was further decomposed into the CH3CH2ONO and CH3CHO with a moderately high energy barrier of 32.87 kcal ⋅ mol-1. Finally, the CH3CH2ONO continues to react with NO2to yield CH3CHO , HNO2and NO with an energy barrier of 28.13 kcal ⋅ mol-1. The calculated oxidation mechanism agrees well with Nishiguchi and Okamoto's experiment and proposal.

scholarly journals A four-coordinate cobalt(II) single-ion magnet with coercivity and a very high energy barrier

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Yvonne Rechkemmer ◽  
Frauke D. Breitgoff ◽  
Margarethe van der Meer ◽  
Mihail Atanasov ◽  
Michael Hakl ◽  
...  
Keyword(s):  
Energy Barrier ◽  
High Energy ◽  
High Energy Barrier ◽  
Very High Energy ◽  
Very High

scholarly journals Rational Electrostatic Design of Easy-Axis Magnetic Anisotropy in a ZnII-DyIII-ZnIISingle-Molecule Magnet with a High Energy Barrier

2014 ◽  
Vol 20 (44) ◽  
pp. 14262-14269 ◽  
Author(s):  
Itziar Oyarzabal ◽  
José Ruiz ◽  
José Manuel Seco ◽  
Marco Evangelisti ◽  
Agustín Camón ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Energy Barrier ◽  
Easy Axis ◽  
High Energy ◽  
High Energy Barrier

scholarly journals First-Principles Investigation of Atomic Hydrogen Adsorption and Diffusion on/into Mo-doped Nb (100) Surface

2018 ◽  
Vol 8 (12) ◽  
pp. 2466 ◽  
Author(s):  
Yang Wu ◽  
Zhongmin Wang ◽  
Dianhui Wang ◽  
Jiayao Qin ◽  
Zhenzhen Wan ◽  
...  
Keyword(s):  
First Principles ◽  
Atomic Hydrogen ◽  
Energy Barrier ◽  
Hydrogen Adsorption ◽  
Hydrogen Permeation ◽  
Diffusion Path ◽  
Interstitial Site ◽  
Octahedral Interstitial Site ◽  
Tetrahedral Interstitial Site ◽  
And Diffusion

To investigate Mo doping effects on the hydrogen permeation performance of Nb membranes, we study the most likely process of atomic hydrogen adsorption and diffusion on/into Mo-doped Nb (100) surface/subsurface (in the Nb12Mo4 case) via first-principles calculations. Our results reveal that the (100) surface is the most stable Mo-doped Nb surface with the smallest surface energy (2.75 J/m2). Hollow sites (HSs) in the Mo-doped Nb (100) surface are H-adsorption-favorable mainly due to their large adsorption energy (−4.27 eV), and the H-diffusion path should preferentially be HS→TIS (tetrahedral interstitial site) over HS→OIS (octahedral interstitial site) because of the correspondingly lower H-diffusion energy barrier. With respect to a pure Nb (100) surface, the Mo-doped Nb (100) surface has a smaller energy barrier along the HS→TIS pathway (0.31 eV).

First-principles study of electronic and diffusion properties of intrinsic defects in 4H-SiC

2020 ◽  
Vol 127 (8) ◽  
pp. 085702 ◽  
Author(s):  
Xiaolan Yan ◽  
Pei Li ◽  
Lei Kang ◽  
Su-Huai Wei ◽  
Bing Huang
Keyword(s):  
First Principles ◽  
Intrinsic Defects ◽  
First Principles Study ◽  
And Diffusion ◽  
Diffusion Properties
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