scholarly journals Adsorption Properties of Pd3-Modified Double-Vacancy Defect Graphene toward SF6 Decomposition Products

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4188
Author(s):  
Jie Li ◽  
Lei Pang ◽  
Fuwei Cai ◽  
Xieyu Yuan ◽  
Fanyu Kong
Keyword(s):  
Density Functional ◽  
Gas Adsorption ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
Vacancy Defect ◽  
Microscopic Mechanism ◽  
Decomposition Products ◽  
Adsorption Structure ◽  
Sf6 Decomposition ◽  
Operation Status

In this study, we investigate Pd3-cluster-modified 555–777 graphene (Pd3-graphene) as a novel resistor-type gas sensor to detect SF6 decomposition products based on density functional theory calculations. We obtained and minutely analyzed the relevant parameters of each most stable adsorption configuration to explore the microscopic mechanism during gas adsorption. Theoretical results reveal that Pd3-graphene shows great adsorption capacity and sensitivity toward those decompositions. High adsorption energies and abundant charge transfer amounts could guarantee a stable adsorption structure of decomposition gases on Pd3-graphene surface. The complex change of density of states verifies a strong chemical reaction between the gases and the surface. Moreover, the conductivity of Pd3-graphene would improve due to the decrease of energy gap, and the sensitivity was calculated as SOF2 > H2S > SO2 > SO2 F2. This work provides an effective method to evaluate the operation status of SF6 gas-insulated equipment.

scholarly journals Mono- and Bi-Molecular Adsorption of SF6 Decomposition Products on Pt Doped Graphene: A First-Principles Investigation

2018 ◽  
Vol 8 (10) ◽  
pp. 2010 ◽  
Author(s):  
Yongqian Wu ◽  
Shaojian Song ◽  
Dachang Chen ◽  
Xiaoxing Zhang
Keyword(s):  
Single Molecule ◽  
First Principles ◽  
Density Functional ◽  
Energy Gap ◽  
Adsorption Parameters ◽  
Functional Theory ◽  
Decomposition Products ◽  
Before And After ◽  
Doped Graphene ◽  
Sf6 Decomposition

Based on the first-principles of density functional theory, the SF6 decomposition products including single molecule (SO2F2, SOF2, SO2), double homogenous molecules (2SO2F2, 2SOF2, 2SO2) and double hetero molecules (SO2 and SOF2, SO2 and SO2F2, SOF2 and SO2F2) adsorbed on Pt doped graphene were discussed. The adsorption parameters, electron transfer, electronic properties and energy gap was investigated. The adsorption of SO2, SOF2 and SO2F2 on the surface of Pt-doped graphene was a strong chemisorption process. The intensity of chemical interactions between the molecule and the Pt-graphene for the above three molecules was SO2F2 > SOF2 > SO2. The change of energy gap was also studied and according to the value of energy gap, the conductivity of Pt-graphene before and after adsorbing different gas molecules can be evaluated.

scholarly journals The Adsorption and Sensing Performances of Ir-modified MoS2 Monolayer toward SF6 Decomposition Products: A DFT Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 100
Author(s):  
Hongcheng Liu ◽  
Feipeng Wang ◽  
Kelin Hu ◽  
Tao Li ◽  
Yuyang Yan ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Density Functional ◽  
Gas Adsorption ◽  
Dft Method ◽  
Orbital Theory ◽  
Gas Sensitivity ◽  
Decomposition Products ◽  
Mos2 Monolayer ◽  
Characteristic Decomposition ◽  
Sensing Material

In this paper, the Ir-modified MoS2 monolayer is suggested as a novel gas sensor alternative for detecting the characteristic decomposition products of SF6, including H2S, SO2, and SOF2. The corresponding adsorption properties and sensing behaviors were systematically studied using the density functional theory (DFT) method. The theoretical calculation indicates that Ir modification can enhance the surface activity and improve the conductivity of the intrinsic MoS2. The physical structure formation, the density of states (DOS), deformation charge density (DCD), molecular orbital theory analysis, and work function (WF) were used to reveal the gas adsorption and sensing mechanism. These analyses demonstrated that the Ir-modified MoS2 monolayer used as sensing material displays high sensitivity to the target gases, especially for H2S gas. The gas sensitivity order and the recovery time of the sensing material to decomposition products were reasonably predicted. This contribution indicates the theoretical possibility of developing Ir-modified MoS2 as a gas sensor to detect characteristic decomposition gases of SF6.

scholarly journals Parametric amplification of optical phonons

2018 ◽  
Vol 115 (48) ◽  
pp. 12148-12151 ◽  
Author(s):  
A. Cartella ◽  
T. F. Nova ◽  
M. Fechner ◽  
R. Merlin ◽  
A. Cavalleri
Keyword(s):  
Density Functional ◽  
Optical Gain ◽  
Density Functional Theory Calculations ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Many Body ◽  
Microscopic Mechanism ◽  
Lattice Mode ◽  
Many Body Interactions ◽  
Kinetics Of

We use coherent midinfrared optical pulses to resonantly excite large-amplitude oscillations of the Si–C stretching mode in silicon carbide. When probing the sample with a second pulse, we observe parametric optical gain at all wavelengths throughout the reststrahlen band. This effect reflects the amplification of light by phonon-mediated four-wave mixing and, by extension, of optical-phonon fluctuations. Density functional theory calculations clarify aspects of the microscopic mechanism for this phenomenon. The high-frequency dielectric permittivity and the phonon oscillator strength depend quadratically on the lattice coordinate; they oscillate at twice the frequency of the optical field and provide a parametric drive for the lattice mode. Parametric gain in phononic four-wave mixing is a generic mechanism that can be extended to all polar modes of solids, as a means to control the kinetics of phase transitions, to amplify many-body interactions or to control phonon-polariton waves.

scholarly journals Oxygen Vacancy Induced Magnetism in Anti-Perovskite Topological Dirac Semimetal Ba3SnO

2021 ◽  
Author(s):  
Javaria Batool ◽  
Syed Muhammad Alay-e-Abbas ◽  
Gustav Johansson ◽  
Waqas Zulfiqar ◽  
Muhammad Arsam Danish ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
Electronic Properties ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Vacancy Defect ◽  
Functional Theory ◽  
Dirac Semimetal

The thermodynamic, structural, magnetic and electronic properties of pristine and intrinsic vacancy defect containing topological Dirac semimetal Ba3SnO are studied using first-principles density functional theory calculations. The thermodynamic stability of...

scholarly journals Large CO2 uptake on a monolayer of CaO

2017 ◽  
Vol 5 (5) ◽  
pp. 2110-2114 ◽  
Author(s):  
G. R. Berdiyorov ◽  
M. Neek-Amal ◽  
I. A. Hussein ◽  
M. E. Madjet ◽  
F. M. Peeters
Keyword(s):  
Density Functional Theory ◽  
Greenhouse Gases ◽  
Strong Interaction ◽  
Density Functional ◽  
Gas Adsorption ◽  
Density Functional Theory Calculations ◽  
Adsorption Properties ◽  
Co2 Uptake ◽  
Uptake Capacity ◽  
Functional Theory

Density functional theory calculations are used to study gas adsorption properties of a recently synthesized CaO monolayer. Due to its topology and strong interaction with the CO2 molecules, this material possesses a remarkably high CO2 uptake capacity and is highly selective towards CO2 against other major greenhouse gases.

Electrical Properties of Single-Walled Carbon Nanotubes due to Compressive Load

2016 ◽  
Vol 675-676 ◽  
pp. 109-112
Author(s):  
Irfan Dwi Aditya ◽  
Sasfan Arman Wella ◽  
Widayani ◽  
Suprijadi
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Compressive Load ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Ab Initio Simulation ◽  
Walled Carbon Nanotubes ◽  
Optimized Geometries

In this paper we report the study of the change in electrical properties of semiconducting carbon nanotubes (CNTs) under uniaxial compressive deformations using the “Vienna ab initio simulation package” (VASP). We present an extension of density functional theory calculations to the electronic properties of the tubes, namely the density of states obtained for the optimized geometries of the tubes. There is an energy gap of 0.772 eV between occupied and unoccupied region in the optimized structure calculation. The band gap for the semi-conducting zigzag (10,0) CNTs decreases as the strain increases. It suggests that the semiconducting CNTs may become semimetal or metal upon deformation.

EFFECTS OF SURFACE OXYGEN ON THE ELECTRONIC PROPERTIES OF SILICON NANOCLUSTERS

2006 ◽  
Vol 05 (01) ◽  
pp. 13-21 ◽  
Author(s):  
YING DAI ◽  
BAIBIAO HUANG ◽  
LIN YU ◽  
SHENGHAO HAN ◽  
DADI DAI
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
Bridge Structure ◽  
Surface Oxygen ◽  
Silicon Nanoclusters ◽  
Silicon Clusters ◽  
Functional Theory

We have studied the effects of surface oxygen and its bond structure on the electronic properties of silicon nanoclusters by means of density functional theory calculations. The results of the energy gap as a function of the nanocluster size in hydrogen-terminated and oxygen-adsorbed silicon clusters provide a well interpretation of several experiments. The nature of electronic and optical properties of silicon nanoclusters has been discussed and attributed to the oxygen in both the Si=O double bond structure and Si–O–Si bridge structure.

First-principles study on codoping effect to enhance photocatalytic activity of anatase TiO2

2017 ◽  
Vol 31 (06) ◽  
pp. 1750036
Author(s):  
Yujie Bai ◽  
Qinfang Zhang ◽  
Fubao Zheng ◽  
Yun Yang ◽  
Qiangqiang Meng ◽  
...  
Keyword(s):  
Visible Light ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
Band Edge ◽  
Electron Hole ◽  
Functional Theory ◽  
Rich Condition

Codopant is an effective approach to modify the bandgap and band edge positions of transition metal oxide. Here, the electronic structures as well as the optical properties of pristine, mono-doped (N/P/Sb) and codoped (Sb, N/P) anatase TiO2 have been systematically investigated based on density functional theory calculations. It is found that mono-doped TiO2 exhibits either unoccupied or partially occupied intermediate state within the energy gap, which promotes the recombination of electron-hole pairs. However, the presence of (Sb, N/P) codopant not only effectively reduces the width of bandgap by introducing delocalized occupied intermediate states, but also adjusts the band edge alignment to enhance the hydrogen evolution activity of TiO2. Moreover, the optical absorption spectrum for (Sb, N/P) codoped TiO2, which is favored under oxygen-rich condition, demonstrates the improvement of its visible light absorption. These findings will promote the potential application of (Sb, N/P) codoped TiO2 photocatalysis for water splitting under visible light irradiation.

SPECTROSCOPIC PROPERTIES OF INDIUM-DOPED CdO NANOSTRUCTURES SUPPORTED BY DFT CALCULATIONS

2019 ◽  
Vol 26 (04) ◽  
pp. 1850169 ◽  
Author(s):  
MUDAR AHMED ABDULSATTAR ◽  
SHATHA SHAMMON BATROS ◽  
ALI J. ADDIE
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Energy Gap ◽  
Cadmium Oxide ◽  
Density Functional Theory Calculations ◽  
Molecular Cluster ◽  
Functional Theory ◽  
Lattice Constants ◽  
In Doping

Indium-doped cadmium oxide nanocrystals are examined using experimental and theoretical techniques. Raman, UV–Vis, and XRD facilities are used to examine Indium-doped CdO nanostructures with three doping ratios 2%, 4% and 6% weight percentages. Density functional theory (DFT) is used to check and compare lattice constants, energy gaps, and Raman vibrational properties. The presently suggested cages for the cubic rock-salt structured clusters adopted by CdO are called cuboids. These cuboids are investigated in bare, and hydrogen surface passivated cases. Experimental results of In-doped CdO show an increase of lattice constants and energy gap. The same trend is observed using density functional theory calculations. The experimental longitudinal optical Raman peak at 556[Formula: see text]cm[Formula: see text] encounters blue shifting to 561.5 [Formula: see text]cm[Formula: see text] at 6% weight percentages In doping. This result is in the same trend using DFT calculations of In-doped CdO hydrogen passivated tetracuboid molecular cluster that shifted from 510.2[Formula: see text]cm[Formula: see text] to 531.3[Formula: see text]cm[Formula: see text] upon In doping. No Burstein–Moss effect is observed by the theoretical model.

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