scholarly journals Performance of Intrinsic and Modified Graphene for the Adsorption of H2S and CH4: A DFT Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 299 ◽  
Author(s):  
Xin Gao ◽  
Qu Zhou ◽  
Jingxuan Wang ◽  
Lingna Xu ◽  
Wen Zeng
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Dft Method ◽  
Vacancy Defect ◽  
Single Vacancy ◽  
Strength Of Interaction ◽  
Before And After ◽  
Doped Graphene ◽  
Weak Adsorption ◽  
Modified Graphene

In this study, the adsorption performances of graphene before and after modification to H2S and CH4 molecules were studied using first principles with the density functional theory (DFT) method. The most stable adsorption configuration, the adsorption energy, the density of states, and the charge transfer are discussed to research the adsorption properties of intrinsic graphene (IG), Ni-doped graphene (Ni–G), vacancy defect graphene (DG), and graphene oxide (G–OH) for H2S and CH4. The weak adsorption and charge transfer of IG achieved different degrees of promotion by doping the Ni atom, setting a single vacancy defect, and adding oxygen-containing functional groups. It can be found that a single vacancy defect significantly enhances the strength of interaction between graphene and adsorbed molecules. DG peculiarly shows excellent adsorption performance for H2S, which is of great significance for the study of a promising sensor for H2S gas.

scholarly journals Sensing Properties of Vacancy and Pd-Doped Graphene Layer: A First-Principles Study

2021 ◽  
Author(s):  
Yanjie Xu ◽  
Jun’an Zhang ◽  
Yunhua Lu ◽  
Qingwei Zhang ◽  
Lei Li ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Adsorption Energy ◽  
Energy Charge ◽  
Vacancy Defect ◽  
Molecular Sensor ◽  
Strength Of Interaction ◽  
Structural And Electronic Properties ◽  
Potential Applications ◽  
Pd Doping ◽  
Doped Graphene

Abstract In this paper, the effect of SO2 adsorption on graphene (intrinsic, vacancy, and doped) is investigated for structural and electronic properties to exploit their potential applications as a gas sensor. The adsorption energy, charge transfer, magnetic moment, density of states, as well as band structure of the SO2 molecule on the vacancy and doped graphene systems are thoroughly discussed. The most stable adsorption site for SO2 on various graphene sheets is also identified and reported. It is found that SO2 molecule is weakly adsorbed on intrinsic graphene (IG) with low adsorption energy. In contrast, vacancy defect and Pd doping significantly enhance the strength of interaction between SO2 molecule and the modified substrates. The dramatic increase in adsorption energy and charge transfer of these systems are expected to induce significant changes in the electrical conductivity of the vacancy graphene (VG) and Pd-doped graphene (PdG) sheets. Furthermore, the results present the potential of Pd-doped vacancy graphene (Pd-VG) for molecular sensor application.

scholarly journals Theoretical Insights into the Electron Capture Behavior of H2SO4···N2O Complex: A DFT and Molecular Dynamics Study

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2349 ◽  
Author(s):  
Wei-Hua Wang ◽  
Wen-Ling Feng ◽  
Wen-Liang Wang ◽  
Ping Li
Keyword(s):  
Molecular Dynamics ◽  
Electron Capture ◽  
Atmospheric Chemistry ◽  
Density Functional ◽  
Molecular Complexes ◽  
Dft Method ◽  
Dynamics Simulation ◽  
Oh Radical ◽  
Before And After ◽  
Reduced Density

Both sulfuric acid (H2SO4) and nitrous oxide (N2O) play a central role in the atmospheric chemistry in regulating the global environment and climate changes. In this study, the interaction behavior between H2SO4 and N2O before and after electron capture has been explored using the density functional theory (DFT) method as well as molecular dynamics simulation. The intermolecular interactions have been characterized by atoms in molecules (AIM), natural bond orbital (NBO), and reduced density gradient (RDG) analyses, respectively. It was found that H2SO4 and N2O can form two transient molecular complexes via intermolecular H-bonds within a certain timescale. However, two molecular complexes can be transformed into OH radical, N2, and HSO4− species upon electron capture, providing an alternative formation source of OH radical in the atmosphere. Expectedly, the present findings not only can provide new insights into the transformation behavior of H2SO4 and N2O, but also can enable us to better understand the potential role of the free electron in driving the proceeding of the relevant reactions in the atmosphere.

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 Study of Pb ion adsorption on (n, 0) CNTs (n=4, 5, 6)

2018 ◽  
Vol 7 (6) ◽  
pp. 469-473 ◽  
Author(s):  
Wei Li ◽  
Yun Zhao ◽  
Teng Wang
Keyword(s):  
Density Functional Theory ◽  
Carbon Nanotube ◽  
Band Gap ◽  
Density Functional ◽  
Ion Adsorption ◽  
Chemical Adsorption ◽  
Adsorption Ability ◽  
Single Vacancy ◽  
Functional Theory ◽  
Before And After

AbstractAbsorption of Pb ion on the (n, 0) carbon nanotube (CNT) (n=4, 5, 6) surface, pure and defected with single vacancy, is investigated based on density functional theory. Pristine (n, 0) CNTs can produce a certain degree of chemical adsorption of Pb ion. While a single vacancy is introduced, the adsorption ability of CNTs for Pb ion increases greatly, and the band gap changes significantly before and after adsorption. SV-(6, 0) CNTs have the strongest adsorption ability, and SV-(5, 0) CNTs are the potential material for the Pb ion detection sensor. It is expected that these could be helpful to the design of Pb filters and sensors.

THEORETICAL STUDY ON PHOTOINDUCED INTRAMOLECULAR CHARGE TRANSFER IN A NOVEL ORGANIC SENSITIZER C201

2011 ◽  
Vol 10 (05) ◽  
pp. 641-649 ◽  
Author(s):  
FENGJIE ZHOU ◽  
YAPING ZHANG ◽  
SHUO CAO ◽  
YONG DING ◽  
SHASHA LIU
Keyword(s):  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Transition Density ◽  
Dft Method ◽  
Transition Dipole Moment ◽  
Transition Dipole ◽  
Level Densities ◽  
Charge Difference Density

A new organic dye (C201) composed of triarylamine unit as electron donor and anchoring unit as electron acceptor, was theoretically investigated by quantum chemical methods. We optimized the geometry of C201 with density functional theory (DFT) at B3LYP/6-311G (d) level. Densities of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), as well as the energies are listed. The excited states of the dye molecules C201 were calculated by time dependent-DFT (TD-DFT) method. Two main visible bands at 572 nm and 407 nm were mainly attributed to the electronic transition from HOMO→LUMO and HOMO-1→LUMO, respectively. 3D cube representations including transition density (TD) and charge difference density (CDD) directly visualized the character of intramolecular charge transfer of C201. The orientation and strength of transition dipole moment were showed visually using TD. Furthermore, we illustrate the orientation and results of the intramolecular charge transfer by CDD.

Al-doped graphene as an effective adsorber for some toxic derivatives of aromatic hydrocarbons

2017 ◽  
Vol 16 (01) ◽  
pp. 1750004 ◽  
Author(s):  
Min Ji ◽  
Xinlu Cheng ◽  
Weidong Wu
Keyword(s):  
Charge Transfer ◽  
Aromatic Hydrocarbons ◽  
Adsorption Energy ◽  
Density Functional ◽  
Hydroxyl Group ◽  
The Density Functional Theory ◽  
Doped Graphene ◽  
Perfect Graphene ◽  
Hydrocarbons Adsorption ◽  
Derivatives Of

The density functional theory (DFT) was used to investigate some toxic derivatives of aromatic hydrocarbons adsorption on perfect graphene (pG) and graphene-doped with B/Al/Ga (BG/AlG/GaG). And the parallel and vertical adsorptions were considered for the position relation between the adsorbent and adsorbate. The adsorption energy, adsorption distance, charge transfer and density of states (DOS) were discussed in optimized structures. The greater adsorption energy, shorter adsorption distance and more charge transfer were found in AlG by studying the four kinds of molecules (phenol/m-cresol/PCP/p-NP) adsorption on pG/BG/AlG/GaG. Then, 10 derivatives adsorption on AlG were reported, and the adsorption energy increased in the order of pentachlorophenol [Formula: see text] 2,4,6-trichlorophenol [Formula: see text] 2,4-dichlorophenol [Formula: see text] p-cresol [Formula: see text] m-cresol [Formula: see text] phenol [Formula: see text] o-chlorophenol [Formula: see text] o-cresol [Formula: see text] 2,4,6-trintrotoluene [Formula: see text] para-nitrophenol. The interaction between these derivatives and the substrate was chemisorption for AlG and physisorption for pG. The oxygen atom in nitro group was more closer to the substrate than in hydroxyl group about optimized structures.

First-principle study of SO2 adsorption on Fe/Co-doped vacancy defected single-walled (8, 0) carbon nanotubes in sensor applications

2019 ◽  
Vol 18 (05) ◽  
pp. 1950025 ◽  
Author(s):  
Meng Zhang ◽  
Guoqing Li ◽  
Xiaomin Lu ◽  
Qianru Zhang ◽  
Wei Li
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Energy Gap ◽  
Single Vacancy ◽  
Functional Theory ◽  
Sensor Applications ◽  
Co Doping ◽  
So2 Adsorption ◽  
Before And After ◽  
Co Doped

To explore the excellent sensor for detecting the pollution gas [Formula: see text], the adsorptions of [Formula: see text] molecule on the surfaces of Fe/Co-doped carbon nanotubes (CNTs) and single vacancy defected (8, 0) CNTs were investigated by using density functional theory (DFT). In addition, the adsorption energies, geometries, energy gaps and electronic structures were analyzed. The results showed that Fe/Co-doping and single-vacancy-defected can improve the adsorption and sensitiveness of CNTs toward [Formula: see text]. Considering the changes of energy gap before and after the [Formula: see text] molecule adsorbed on each modified CNTs and its adsorption strength, Fe-doped CNTs (Fe-CNTs) and Co-doped site-2 single-vacancy-defected CNTs performed better for detecting [Formula: see text] molecule. With the decreasing number of electrons of the doped atom (Fe, Co, Ni), the adsorption became more stable. The results of this paper are profound and meaningful for designing [Formula: see text] sensing devices.

Molecular Oxygen Adsorbed on Gallium Doped Graphene: A First-Principles Study

2017 ◽  
Vol 890 ◽  
pp. 117-120
Author(s):  
Seba Sara Varghese ◽  
Sundaram Swaminathan ◽  
Krishna Kumar Singh ◽  
Vikas Mittal
Keyword(s):  
Electronic Properties ◽  
Molecular Oxygen ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Strong Interactions ◽  
Functional Theory ◽  
Before And After ◽  
Doped Graphene

The adsorption of molecular oxygen on gallium doped graphene sheet is investigated using first-principles density functional theory calculations. The adsorption energy of O2 on gallium doped graphene is calculated after determining the energetically favourable adsorption configuration. The change in the electronic properties of gallium doped graphene after O2 adsorption is also determined to understand the nature their interactions. The results show that gallium doped graphene has large adsorption energy and small binding distance, which correspond to chemical adsorption. The calculated band structure and density of states plots of gallium doped graphene before and after adsorption show dramatic changes in the electronic properties due to the strong interactions of gallium doped graphene with adsorbed O2 molecule. These results indicate that gallium doped graphene is highly reactive to molecular oxygen and hence not a suitable choice for harmful gas detection in the presence of O2.

H2 ADSORPTION ON LiB (001) SURFACE: A FIRST PRINCIPLES CALCULATION

2012 ◽  
Vol 11 (04) ◽  
pp. 781-790 ◽  
Author(s):  
WEI-BIN ZHANG ◽  
WEI-DONG WU ◽  
XIN-LU CHENG ◽  
XUE-MIN WANG ◽  
HAI-PING WANG ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Dft Method ◽  
First Principles Calculation ◽  
Partial Density ◽  
Functional Theory ◽  
H2 Adsorption ◽  
Partially Saturated ◽  
Before And After ◽  
Density Band

The adsorption behavior of H2 on the LiB (001) surface was investigated with density functional theory (DFT) method. It was found that the site of H2 adsorbed on the Li-B bridge II was easier than the other four sites ( Li top, B top, hollow vertical and Li-B bridge I). H2 adsorbed on the Li-B bridge II site was a strong chemical adsorption. The adsorption energy was 2.190 eV, and the H , B atoms exhibited covalent characteristics, the H – H atoms have a little interaction, and the H2 was 0.331 Å below the surface of Li-B bridge II. The charge density, band structure, totals and partial density of states were calculated utilizing the first principle method. These calculations showed that the H interacted with the surface atoms, and partially saturated the dangling bonds with the surface atoms. The interaction between H and the surface atoms were mainly attributed to the H 1 s, B 2 s and B 2 p states. The calculated band gap was 0.075 eV and 0.199 eV before and after adsorption.

scholarly journals CO2 Adsorption on PtCu Sub-Nanoclusters Deposited on Pyridinic N-Doped Graphene: A DFT Investigation

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7619
Author(s):  
Fernando Montejo-Alvaro ◽  
Diego González-Quijano ◽  
Jorge A. Valmont-Pineda ◽  
Hugo Rojas-Chávez ◽  
José M. Juárez-García ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Co2 Adsorption ◽  
Value Added ◽  
Co2 Concentration ◽  
Binding Energies ◽  
The Density Functional Theory ◽  
Doped Graphene ◽  
The Stability ◽  
Pyridinic N

To reduce the CO2 concentration in the atmosphere, its conversion to different value-added chemicals plays a very important role. Nevertheless, the stable nature of this molecule limits its conversion. Therefore, the design of highly efficient and selective catalysts for the conversion of CO2 to value-added chemicals is required. Hence, in this work, the CO2 adsorption on Pt4-xCux (x = 0–4) sub-nanoclusters deposited on pyridinic N-doped graphene (PNG) was studied using the density functional theory. First, the stability of Pt4-xCux (x = 0–4) sub-nanoclusters supported on PNG was analyzed. Subsequently, the CO2 adsorption on Pt4-xCux (x = 0–4) sub-nanoclusters deposited on PNG was computed. According to the binding energies of the Pt4-xCux (x = 0–4) sub-nanoclusters on PNG, it was observed that PNG is a good material to stabilize the Pt4-xCux (x = 0–4) sub-nanoclusters. In addition, charge transfer occurred from Pt4-xCux (x = 0–4) sub-nanoclusters to the PNG. When the CO2 molecule was adsorbed on the Pt4-xCux (x = 0–4) sub-nanoclusters supported on the PNG, the CO2 underwent a bond length elongation and variations in what bending angle is concerned. In addition, the charge transfer from Pt4-xCux (x = 0–4) sub-nanoclusters supported on PNG to the CO2 molecule was observed, which suggests the activation of the CO2 molecule. These results proved that Pt4-xCux (x = 0–4) sub-nanoclusters supported on PNG are adequate candidates for CO2 adsorption and activation.

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