scholarly journals A DFT Study on the Adsorption of H2S and SO2 on Ni Doped MoS2 Monolayer

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 646 ◽  
Author(s):  
Huangli Wei ◽  
Yingang Gui ◽  
Jian Kang ◽  
Weibo Wang ◽  
Chao Tang
Keyword(s):  
Density Of States ◽  
Adsorption Energy ◽  
First Principles ◽  
Structural Parameters ◽  
Energy Charge ◽  
Interaction Mechanism ◽  
First Principles Calculation ◽  
Mos2 Monolayer ◽  
Strong Adsorption ◽  
Main Decomposition

In this paper, a Ni-doped MoS2 monolayer (Ni-MoS2) has been proposed as a novel gas adsorbent to be used in SF6-insulated equipment. Based on the first-principles calculation, the adsorption properties of Ni-MoS2 to SO2 and H2S molecules, the main decomposition components of SF6 under a partial discharge (PD) condition have been studied. The adsorption energy, charge transfer, and structural parameters have been analyzed to find the most stable gas-adsorbed Ni-MoS2. Furthermore, the density of states (DOS), projected density of states (PDOS), and electron density difference were employed to explore the interaction mechanism between SO2, H2S, and the Ni-MoS2 surface. It is found that the H2S molecule and SO2 molecule interact with the Ni-MoS2 surface by strong adsorption energy. Therefore, we conclude that the interaction between these two kinds of gases and the Ni-MoS2 monolayer belongs to chemisorption, and the Ni-MoS2 monolayer might be a promising gas adsorbent for the fault recovery of SF6-insulated equipment. Additionally, we have to point out that all of the conclusions only considered the final adsorption energy, the barrier in the transition state has not been analyzed in this paper.

scholarly journals First-Principles Calculation of Adsorption of Shale Gas on CaCO3 (100) Surfaces

2017 ◽  
Vol 15 (1_suppl) ◽  
pp. 45-51 ◽  
Author(s):  
Qiang Luo ◽  
Yikun Pan ◽  
Ping Guo ◽  
Zhouhua Wang ◽  
Na Wei ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Density Of States ◽  
Shale Gas ◽  
Adsorption Energy ◽  
First Principles ◽  
First Principles Calculation ◽  
High Symmetry ◽  
Hydrogen Atoms ◽  
Adsorption Effect ◽  
Before And After

Background To demonstrate the adsorption strength of shale gas to calcium carbonate in shale matrix, the adsorption of shale gas on CaCO3 (100) surfaces was studied using the first-principles method, which is based on the density functional theory (DFT). Methods The structures and electronic properties of CH4, C2H6, CO2 and N2 molecules were calculated by the generalized gradient approximation (GGA), for a coverage of 1 monolayer (ML). Under the same conditions, the density of states (DOS) of CaCO3 (100) surfaces before and after the adsorption of shale gas molecules at high-symmetry adsorption sites were compared. Results The results showed that the adsorption energies of CH4, C2H6, CO2 and N2 on CaCO3 (100) surfaces were between 0.2683 eV and -0.7388 eV. When a CH4 molecule was adsorbed at a hollow site and its 2 hydrogen atoms were parallel to the long diagonal (H3) on the CaCO3 (100) surface, it had the most stable adsorption, and the adsorption energy was only -0.4160 eV. The change of adsorption energy of CH4 was no more than 0.0535 eV. Compared with the DOS distribution of CH4 before adsorption, it shifted to the left overall after adsorption. At the same time, the partial density of states (PDOS) curves of CaCO3 (100) surfaces before and after adsorption basically overlapped. Conclusions This work showed that the adsorption effect of shale gas on calcium carbonate is very weak, and the adsorption is physisorption at the molecular level.

First-principles study of electronic structure, chemical bonding and elastic properties for new superconductor CaFeAs2

2017 ◽  
Vol 31 (02) ◽  
pp. 1650263
Author(s):  
J. G. Yan ◽  
Z. J. Chen ◽  
G. B. Xu ◽  
Z. Kuang ◽  
T. H. Chen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
Density Of States ◽  
First Principles ◽  
Elastic Anisotropy ◽  
First Principles Calculation ◽  
Hard Material ◽  
Dirac Cone ◽  
First Time ◽  
New Superconductor

Using first-principles calculation we investigated the structural, electronic and elastic properties of paramagnetic CaFeAs2. Our results indicated that the density of states (DOS) was dominated predominantly by Fe-3[Formula: see text] states at Fermi levels, and stronger hybridization exists between As1 and As1 atoms. Three hole pockets are formed at [Formula: see text] and Z points, and two electronic pockets are formed at A and E points. The Dirac cone-like bands appear near B and D points. For the first time we calculated the elastic properties and found that CaFeAs2 is a mechanically stable and moderately hard material, it has elastic anisotropy and brittleness, which agrees well with the bonding picture and the calculation of Debye temperature ([Formula: see text]).

Electric Field Controlled Separation and Capture of CO2 over S-Doped Graphene: A First-Principles Calculation

2021 ◽  
Vol 43 (6) ◽  
pp. 623-623
Author(s):  
Jingyi Shan Jingyi Shan ◽  
Xiangling Wang Xiangling Wang ◽  
Junkai Wang Junkai Wang ◽  
Shixuan Zhang Shixuan Zhang ◽  
Qianku Hu and Aiguo Zhou Qianku Hu and Aiguo Zhou
Keyword(s):  
Electric Field ◽  
Adsorption Energy ◽  
Greenhouse Effect ◽  
First Principles ◽  
Applied Electric Field ◽  
Density Functional ◽  
Selective Adsorption ◽  
First Principles Calculation ◽  
Combustion Gases ◽  
Doped Graphene

The selective adsorption and capture of CO2 from post-combustion gases carries huge significance for the reduction of greenhouse effect. In this research, the computations of density functional are performed to investigate the CO2 selective adsorption of S-doped graphene in thrall to applied electric field (E-F). Introducing the applied E-F, the adsorption between S-doped graphene and CO2 is strong chemisorption, and CO2 can be effectively captured. Removing the applied E-F, the adsorption restores to physisorption and CO2 is easily desorbed. Therefore, the CO2 seize and clearing can be realized merely by controlling the E-F. Besides, the adsorption energy of N2 (H2O) on S-decorated graphene is positive when introduce the applied E-F. The results demonstrated that S-doped graphene can selectively adsorb CO2 from the post-combustion gases by controlling the E-F.

First Principles Calculation on Adsorption of S on Impurity Fe (100)

2012 ◽  
Vol 472-475 ◽  
pp. 1538-1543
Author(s):  
Qiang Luo ◽  
Zhi Zhang ◽  
Qiang Zhang ◽  
Tai He Shi ◽  
Zeng Ling Ran
Keyword(s):  
Electronic Properties ◽  
Density Function ◽  
Molecular Orbital ◽  
Adsorption Energy ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation

Using the first principles method, which is based on the density function theory (DFT), the structures and electronic properties of S atoms are adsorbed on the Fe (100) surface for X(X is Cr, Ni, Mo, C, Mn ,Si,P and S) impurities in Fe, and their molecular orbital and absorption energies were calculated with the generalized gradient approximation. The results show that S adsorbed on H site for Cr, Ni, Mn, C and Mo impurities in Fe is stable but for Si, S and P is B site. The adsorption energy for Ni in impurity Fe is almost nearby for the purity Fe and the effect for Ni in S absorption on Fe (100) surface is very small. In order to prevent S absorption on Fe surface，we can reduce the percentage of Ni.

Grain Refining Behavior of Zr, Al2Y and Al4C3 Particles in Magnesium Alloys by the First-Principles Calculations

2015 ◽  
Vol 816 ◽  
pp. 370-374
Author(s):  
Jun Ling Pan ◽  
Qiu Ming Peng ◽  
Jian Xin Guo ◽  
Hui Li
Keyword(s):  
Mechanical Properties ◽  
Structural Optimization ◽  
Magnesium Alloys ◽  
Density Of States ◽  
Adsorption Energy ◽  
First Principles ◽  
Adsorption Process ◽  
Mg Alloys ◽  
Grain Refining ◽  
First Principles Calculations

Grain refining is one of the most important issues in the applications of Mg alloys, which directly determines mechanical properties and deformability. Therefore the understanding of grain refining mechanism during solidification will be benefit to develop new grain refiners. Herein refining role was elucidated by the first principles calculations based on adsorption behavior of a Mg atom on the closest-packed planes of grain refiners (Zr (001), Al2Y(311) and Al4C3(102)). Taking into account different sites, the site with the maximum adsorption energy value generally corresponded to the most possible location. The adsorption energy results show that the possible refining turn follows Al4C3(102)>Zr (001)>Al2Y(311). Meanwhile, the structural optimization confirmed that the Mg atom connected with two C atoms on the top of zig-zag plane of Al4C3(102), three Zr atoms at the hcp position on Zr (001), and two Y atoms and one Al atom at the bottom of zig-zag plane of Al2Y(311). The density of states revealed that the variation of d-orbital electrons of Mg atom became apparent during adsorption process. The values of Mulliken charges were 0.898 e in Al4C3(102), 0.410 e in Zr (001) and 0.245 e in Al2Y(311), respectively. This tendency agrees well with the previous experimental results. It indicates the adsorption energy on the closest-packed planes can be regarded as a prerequisite to select new grain refiners for Mg alloys in future.

scholarly journals First Principles Study of Gas Molecules Adsorption on Monolayered β-SnSe

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 390 ◽  
Author(s):  
Tianhan Liu ◽  
Hongbo Qin ◽  
Daoguo Yang ◽  
Guoqi Zhang
Keyword(s):  
Gas Sensors ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Adsorption Properties ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Β Phase ◽  
Physical Sensor ◽  
Gas Molecules

For the purpose of exploring the application of two-dimensional (2D) material in the field of gas sensors, the adsorption properties of gas molecules, CO, CO2, CH2O, O2, NO2, and SO2 on the surface of monolayered tin selenium in β phase (β-SnSe) has been researched by first principles calculation based on density functional theory (DFT). The results indicate that β-SnSe sheet presents weak physisorption for CO and CO2 molecules with small adsorption energy and charge transfers, which show that a β-SnSe sheet is not suitable for sensing CO and CO2. The adsorption behavior of CH2O molecules adsorbed on a β-SnSe monolayer is stronger than that of CO and CO2, revealing that the β-SnSe layer can be applied to detect CH2O as physical sensor. Additionally, O2, NO2, and SO2 are chemically adsorbed on a β-SnSe monolayer with moderate adsorption energy and considerable charge transfers. All related calculations reveal that β-SnSe has a potential application in detecting and catalyzing O2, NO2, and SO2 molecules.

scholarly journals Pressure Effect of the Vibrational and Thermodynamic Properties of Chalcopyrite-Type Compound AgGaS2: A First-Principles Investigation

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2370 ◽  
Author(s):  
Jianhui Yang ◽  
Qiang Fan ◽  
You Yu ◽  
Weibin Zhang
Keyword(s):  
Thermal Conductivity ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Structural Parameters ◽  
Structural Phase ◽  
First Principles Calculation ◽  
Optical Phonons ◽  
Phonon Modes ◽  
Type Compound ◽  
Center Point

To explore the structural, vibrational, and thermodynamic properties of the chalcopyrite-type compound AgGaS2 under pressure, we applied hydrostatic pressure to the relaxed compound based on the first principles calculation and quasi-harmonic approximation. The structural parameters, including lattice constants and bond lengths decrease monotonically with the increasing pressure. The phonon dispersion curves under various pressures reveal the structural phase transition of chalcopyrite-type compound AgGaS2 at about 4 GPa. The intrinsic mechanism of thermal conductivity for the chalcopyrite-type compound AgGaS2 has been shown with phonon anharmonicity. The frequencies of the optical phonons at the center point Γ of the first Brillouin zone were calculated with the longitudinal optical–transverse optical (LO–TO) splitting mode. The dependence of the frequencies of the optical phonons on the pressure provides the information for the Raman spectroscopic study under high pressure. The pressure dependence of the Grüneisen parameters indicates that the instability of chalcopyrite-type compound AgGaS2 is associated with the softening of the acoustic phonon modes at around the center point Γ. The thermal conductivity for chalcopyrite-type compound AgGaS2 could be reduced by applying external pressure. The various thermodynamic properties, such as the Helmholtz free energy, entropy, and heat capacity, at different temperatures and pressures were discussed and analyzed based on the phonon properties.

Sign in / Sign up

Export Citation Format

Share Document