First-Principles Study of the Calcium Insertion in Layered and Non-Layered Phases of Vanadia

MRS Advances ◽  
2018 ◽  
Vol 3 (60) ◽  
pp. 3507-3512 ◽  
Author(s):  
Daniel Koch ◽  
Sergei Manzhos
Keyword(s):  
First Principles ◽  
Vanadium Dioxide ◽  
Calcium Ion ◽  
Density Functional ◽  
Host Lattice ◽  
Functional Theory ◽  
Suitable Material ◽  
Low Concentrations ◽  
Oxide Phases ◽  
Insight Into

ABSTRACTWe investigate the insertion energetics of Ca at low concentrations in four promising vanadium oxide phases (α and δ vanadium pentoxide (V2O5) polymorphs as well as rutile- (R) and bronze-type (B) vanadium dioxide (VO2)) using density functional theory (DFT). We find α-V2O5 to be the most suitable material for an application as cathode, driven by a stable coordinative environment, while VO2(R) does not exhibit a stable low-concentration CaxVO2 phase due to severe distortions of the host lattice due to the large calcium ion. The results provide insight into the possibility of employing these phases as active cathode materials of Ca-ion batteries.

Nano-sized nickel catalyst for deep hydrogenation of lignin monomers and first-principles insight into the catalyst preparation

2017 ◽  
Vol 5 (8) ◽  
pp. 3948-3965 ◽  
Author(s):  
Shi-Chao Qi ◽  
Lu Zhang ◽  
Hisahiro Einaga ◽  
Shinji Kudo ◽  
Koyo Norinaga ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Full Range ◽  
Catalyst Preparation ◽  
Ni Catalyst ◽  
Borohydride Reduction ◽  
Functional Theory ◽  
Pyridine Complex ◽  
Insight Into

A type of nano-sized Ni catalyst supported by ZSM-5 zeolite for the deep hydrogenation of lignin monomers is prepared by borohydride reduction of a Ni2+–pyridine complex in ethanol. The mechanism of the borohydride reduction over the full range from Ni2+ to Ni0 is calculated by applying density functional theory.

scholarly journals Applications of DFT + DMFT in Materials Science

2019 ◽  
Vol 49 (1) ◽  
pp. 31-52 ◽  
Author(s):  
Arpita Paul ◽  
Turan Birol
Keyword(s):  
Field Theory ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Materials Science ◽  
Mean Field Theory ◽  
Mean Field ◽  
Dynamical Mean Field Theory ◽  
Functional Theory ◽  
Insight Into

First-principles methods can provide insight into materials that is otherwise impossible to acquire. Density functional theory (DFT) has been the first-principles method of choice for numerous applications, but it falls short of predicting the properties of correlated materials. First-principles DFT + dynamical mean field theory (DMFT) is a powerful tool that can address these shortcomings of DFT when applied to correlated metals. In this brief review, which is aimed at nonexperts, we review the basics and some applications of DFT + DMFT.

First-principles insight into CO hindered agglomeration of Rh and Pt single atoms on ZrO2

2020 ◽  
Author(s):  
Minttu M. Kauppinen ◽  
Marko Melander ◽  
Karoliina Honkala
Keyword(s):  
First Principles ◽  
Density Functional ◽  
High Vacuum ◽  
Kinetic Stability ◽  
Ultra High Vacuum ◽  
Functional Theory ◽  
Single Atoms ◽  
Atomistic Thermodynamics ◽  
Using Data ◽  
Insight Into

<div><div><div><p>In this first-principles study we evaluate the thermodynamic and kinetic stability of Rh and Pt single-atoms (SAs) and subnano clusters on the monoclinic zirconia surface with and without a CO atmosphere. To address the kinetic stability and agglomeration of SAs to clusters and nanoparticles, a non-equilibrium nanothermodynamic approach is developed and parametrised using data computed with density functional theory. The bare subnano clusters are more stable than SA and become more so with increasing size, which means the agglomeration is always favoured. CO binds strongly to the single atoms and clusters, and our atomistic thermodynamics treatment indicates that some CO will be present even at ultra-high vacuum conditions. A CO atmosphere is shown to hinder cluster growth from SA, and is even capable of spontaneous cluster disintegration in the case of Pt clusters. Analysis of the CO stretching frequencies reveals that subnano clusters and single atoms should give peaks in the same region, and that using them to distinguish between surface species requires caution.</p></div></div></div>

First-principles insight into CO hindered agglomeration of Rh and Pt single atoms on ZrO2

2020 ◽  
Author(s):  
Minttu M. Kauppinen ◽  
Marko Melander ◽  
Karoliina Honkala
Keyword(s):  
First Principles ◽  
Density Functional ◽  
High Vacuum ◽  
Kinetic Stability ◽  
Ultra High Vacuum ◽  
Functional Theory ◽  
Single Atoms ◽  
Atomistic Thermodynamics ◽  
Using Data ◽  
Insight Into

<div><div><div><p>In this first-principles study we evaluate the thermodynamic and kinetic stability of Rh and Pt single-atoms (SAs) and subnano clusters on the monoclinic zirconia surface with and without a CO atmosphere. To address the kinetic stability and agglomeration of SAs to clusters and nanoparticles, a non-equilibrium nanothermodynamic approach is developed and parametrised using data computed with density functional theory. The bare subnano clusters are more stable than SA and become more so with increasing size, which means the agglomeration is always favoured. CO binds strongly to the single atoms and clusters, and our atomistic thermodynamics treatment indicates that some CO will be present even at ultra-high vacuum conditions. A CO atmosphere is shown to hinder cluster growth from SA, and is even capable of spontaneous cluster disintegration in the case of Pt clusters. Analysis of the CO stretching frequencies reveals that subnano clusters and single atoms should give peaks in the same region, and that using them to distinguish between surface species requires caution.</p></div></div></div>

scholarly journals First-Principles Study of Thermo-Physical Properties of Pu-Containing Gd2Zr2O7

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 196
Author(s):  
Pengcheng Li ◽  
Fengai Zhao ◽  
Haiyan Xiao ◽  
Haibin Zhang ◽  
Hengfeng Gong ◽  
...  
Keyword(s):  
Physical Properties ◽  
First Principles ◽  
Density Functional ◽  
Structural Parameters ◽  
Mechanical And Thermal Properties ◽  
Functional Theory ◽  
Waste Immobilization ◽  
Nuclear Waste Immobilization ◽  
Thermo Physical Properties ◽  
Insight Into

A density functional theory plus Hubbard U method is used to investigate how the incorporation of Pu waste into Gd2Zr2O7 pyrochlore influences its thermo-physical properties. It is found that immobilization of Pu at Gd-site of Gd2Zr2O7 has minor effects on the mechanical and thermal properties, whereas substitution of Pu for Zr-site results in remarkable influences on the structural parameters, elastic moduli, elastic isotropy, Debye temperature and electronic structure. The discrepancy in thermo-physical properties between Gd2−yPuyZr2O7 and Gd2Zr2−yPuyO7 may be a result of their different structural and electronic structures. This study provides a direct insight into the thermo-physical properties of Pu-containing Gd2Zr2O7, which will be important for further investigation of nuclear waste immobilization by pyrochlores.

Adsorption of Methane on the (100) Surface of MgO: Insight into Surface-Adsorbate and Adsorbate-Adsorbate Interactions from First-Principles Calculations

2006 ◽  
Vol 928 ◽  
Author(s):  
Michael L Drummond ◽  
Bobby G Sumpter ◽  
William A Shelton ◽  
John Z Larese
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Energy Structure ◽  
First Principles Calculations ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Adsorption Of Methane ◽  
Insight Into

ABSTRACTFirst principles calculations using density functional theory (DFT) are reported for two layers of methane adsorbed on the (100) surface of MgO. The lowest energy structure determined has a first layer with C2v methanes adsorbed above magnesium atoms, with hydrogen atoms pointed towards neighboring oxygen atoms, and a rotation of 90° in between each neighboring methane. The second layer methane layer has a similar structure, except the hydrogen atoms are directed towards nearest neighbor magnesium atoms. It is found that the structure of the first layer has a large effect on the relative energies of proposed bilayer structures, as does the calculated separation between the two layers of methane. Competing roles of surface-adsorbate and adsorbate-adsorbate interactions are also discussed.

Effect of the alloying element titanium on the stability and trapping of hydrogen in pure vanadium: A first-principles study

2014 ◽  
Vol 28 (29) ◽  
pp. 1450207 ◽  
Author(s):  
Juan Hua ◽  
Yue-Lin Liu ◽  
Heng-Shuai Li ◽  
Ming-Wen Zhao ◽  
Xiang-Dong Liu
Keyword(s):  
Binary Alloy ◽  
First Principles ◽  
Density Functional ◽  
Interstitial Site ◽  
Alloying Element ◽  
Functional Theory ◽  
Vacancy Defects ◽  
Tetrahedral Interstitial Site ◽  
The Stability ◽  
Insight Into

With a first-principles method based on density functional theory, the effect of the alloying element titanium ( Ti ) on the thermodynamic stability and electronic structure of hydrogen ( H ) in pure vanadium ( V ) is investigated. The interactions between H and the vacancy and the defect solution energies in a dilute V – Ti binary alloy are calculated. The results show that: (i) a single H atom prefers to reside in a tetrahedral interstitial site in dilute V – Ti binary alloy systems; (ii) H atoms tend to bond at the vacancy sites; a mono-vacancy is shown to be capable of trapping three H atoms; and (iii) the presence of Ti in pure V can increase the H trapping energy and reduce the H trapping capability of the vacancy defects. This indicates that doping with Ti to form dilute V – Ti binary alloys can inhibit the solution for H , and thus suppress the retention of H . These results provide useful insight into V -based alloys as a candidate structural material in fusion reactors.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

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