scholarly journals Hydrogenation of Substituted Fullerenes – a DFT Study

2017 ◽  
Vol 6 (2) ◽  
pp. 139
Author(s):  
K. Muthukumar ◽  
M. Sankaran ◽  
B. Viswanathan
Keyword(s):  
Hydrogen Storage ◽  
Dissociation Energy ◽  
Density Functional ◽  
Hydrogen Molecule ◽  
Carbon Materials ◽  
Fullerene Molecule ◽  
Density Functional Theory Calculations ◽  
Model Systems ◽  
The Density Functional Theory ◽  
Forms Of Carbon

Hydrogen storage by carbon materials is a topic of current interest. In order to exploit fullerenes as one of the new forms of carbon for hydrogen storage, it is shown that an activator for hydrogen is necessary in the fullerene network. Even though one can generate stoichiometric hydrides the formation of such hydrides have to be established. In this present study we have examined what type of species on carbon surfaces may be able to activate hydrogen molecule and lead to hydride formation. The Density Functional Theory calculations have been carried out on some typical model systems wherein the fullerene molecule is substituted in the network with heteroatoms like N, P and S and the reduction in the dissociation energy of hydrogen molecule is considered as a measure of the ability to hydride the carbon materials. On the basis of the reduction in the dissociation energy for the hydrogen molecule it was shown that heteroatom substitution in the fullerene net work may be suitable for the activation and dissociation of hydrogen molecule.

Adsorption of Hydrogen Molecule on the Intrinsic and Al-Doped Graphene: A First Principle Study

2012 ◽  
Vol 507 ◽  
pp. 61-64 ◽  
Author(s):  
Ye Lu He ◽  
Ding Xing Liu ◽  
Yong Qu ◽  
Zhen Yao
Keyword(s):  
Hydrogen Storage ◽  
Density Functional ◽  
Hydrogen Molecule ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculations ◽  
Hydrogen Storage Material ◽  
Storage Material ◽  
Promising Candidate ◽  
Functional Theory ◽  
Doped Graphene

The adsorption hydrogen molecule on intrinsic and Al-doped graphene was studied by density functional theory calculations. The results show that the intrinsic graphene is not an ideal hydrogen storage material. Compared with the intrinsic, H2 molecules are stongly adsorbed onto the Al-doped graphene with higher adsorbed energy and shorter distance between H2 and surface. The band structure and density of states results show that between hydrogen and other atoms, the charge transfers are apparent increased. All are help for hydrogen adsorption. Therefore, Al-doped graphene is a promising candidate for hydrogen storage material.

scholarly journals Synthesis, Mass Spectroscopy Detection, and Density Functional Theory Investigations of the Gd Endohedral Complexes of C82 Fullerenols

Computation ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 58
Author(s):  
Anastasia A. Shakirova ◽  
Felix N. Tomilin ◽  
Vladimir A. Pomogaev ◽  
Natalia G. Vnukova ◽  
Grigory N. Churilov ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Mass Spectrometry Analysis ◽  
Structure And Properties ◽  
Functional Theory ◽  
Endohedral Complexes ◽  
Spectrometry Analysis ◽  
The Density Functional Theory ◽  
Atomic And Electronic Structure

Gd endohedral complexes of C82 fullerenols were synthesized and mass spectrometry analysis of their composition was carried out. It was established that the synthesis yields a series of fullerenols Gd@C82Ox(OH)y (x = 0, 3; y = 8, 16, 24, 36, 44). The atomic and electronic structure and properties of the synthesized fullerenols were investigated using the density functional theory calculations. It was shown that the presence of endohedral gadolinium increases the reactivity of fullerenols. It is proposed that the high-spin endohedral fullerenols are promising candidates for application in magnetic resonance imaging.

scholarly journals Molecular Insights into Cage Occupancy of Hydrogen Hydrate: A Computational Study

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 699 ◽  
Author(s):  
Ma ◽  
Zhong ◽  
Liu ◽  
Zhong ◽  
Yan ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Storage ◽  
Molecular Dynamics Simulations ◽  
Density Functional ◽  
Storage Capacity ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
Hydrogen Storage Capacity ◽  
Large Cage ◽  
Dynamics Simulations

Density functional theory calculations and molecular dynamics simulations were performed to investigate the hydrogen storage capacity in the sII hydrate. Calculation results show that the optimum hydrogen storage capacity is ~5.6 wt%, with the double occupancy in the small cage and quintuple occupancy in the large cage. Molecular dynamics simulations indicate that these multiple occupied hydrogen hydrates can occur at mild conditions, and their stability will be further enhanced by increasing the pressure or decreasing the temperature. Our work highlights that the hydrate is a promising material for storing hydrogen.

Theoretical study of SnS2 encapsulated in Graphene as a promising anode material for K−ion batteries

2021 ◽  
Author(s):  
Xuxin Kang ◽  
Wei Xu ◽  
Xiangmei Duan
Keyword(s):  
Anode Material ◽  
Density Functional ◽  
Open Circuit Voltage ◽  
Electronic Conductivity ◽  
Density Functional Theory Calculations ◽  
Rechargeable Batteries ◽  
Open Circuit ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Low K

Abstract Rechargeable batteries with superior electronic conductivity, large capacity, low diffusion barriers and moderate open circuit voltage have attracted amount attention. Due to abundant resources and safety, as well as the high voltage and energy density, potassium ion batteries (KIBs) could be an ideal alternative to next−generation of rechargeable batteries. Based on the density functional theory calculations, we find that the SnS2 monolayer expands greatly during the potassiumization, which limits its practical application. The construction of graphene/SnS2/graphene (G/SnS2/G) heterojunction effectively prevents SnS2 sheet from deformation, and enhances the electronic conductivity. Moreover, the G/SnS2/G has not only a high theoretical special capacity of 680 mAh/g, but an ultra−low K diffusion barrier (0.08 eV) and an average open circuit voltage (0.22 V). Our results predict that the G/SnS2/G heterostructure could be used as a promising anode material for KIBs.

scholarly journals Flat Band and Hole-induced Ferromagnetism in a Novel Carbon Monolayer

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jing-Yang You ◽  
Bo Gu ◽  
Gang Su
Keyword(s):  
Density Functional ◽  
Doping Concentration ◽  
Carbon Materials ◽  
Density Functional Theory Calculations ◽  
Hole Doping ◽  
Flat Band ◽  
Ferromagnetic Transition ◽  
Functional Theory ◽  
Flat Bands ◽  
Half Metal

AbstractIn recent experiments, superconductivity and correlated insulating states were observed in twisted bilayer graphene (TBG) with small magic angles, which highlights the importance of the flat bands near Fermi energy. However, the moiré pattern of TBG consists of more than ten thousand carbon atoms that is not easy to handle with conventional methods. By density functional theory calculations, we obtain a flat band at EF in a novel carbon monolayer coined as cyclicgraphdiyne with the unit cell of eighteen atoms. By doping holes into cyclicgraphdiyne to make the flat band partially occupied, we find that cyclicgraphdiyne with 1/8, 1/4, 3/8 and 1/2 hole doping concentration shows ferromagnetism (half-metal) while the case without doping is nonmagnetic, indicating a hole-induced nonmagnetic-ferromagnetic transition. The calculated conductivity of cyclicgraphdiyne with 1/8, 1/4 and 3/8 hole doping concentration is much higher than that without doping or with 1/2 hole doping. These results make cyclicgraphdiyne really attractive. By studying several carbon monolayers, we find that a perfect flat band may occur in the lattices with both separated or corner-connected triangular motifs with only including nearest-neighboring hopping of electrons, and the dispersion of flat band can be tuned by next-nearest-neighboring hopping. Our results shed insightful light on the formation of flat band in TBG. The present study also poses an alternative way to manipulate magnetism through doping flat band in carbon materials.

scholarly journals Large Uniaxial Magnetic Anisotropy of Hexagonal Fe-Hf-Sb Alloys

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 430
Author(s):  
Lukas Kyvala ◽  
Maxim Tchaplianka ◽  
Alexander Shick ◽  
Sergii Khmelevskyi ◽  
Dominik Legut
Keyword(s):  
Density Functional Theory ◽  
Magnetic Anisotropy ◽  
Permanent Magnet ◽  
Chemical Control ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Magnetization Direction ◽  
Functional Theory ◽  
Uniaxial Magnetic Anisotropy ◽  
The Density Functional Theory

We theoretically investigate the electronic and magnetic structure of Fe 2 Hf. The density functional theory calculations are shown to produce the negative, easy-plane, magnetic anisotropy in the hexagonal Fe 2 Hf. Antimony substitution suppresses the planar magnetization direction and favors the uniaxial magnetic anisotropy, in agreement with experimental observations. Our study suggests the possibility of the chemical control of the magnetic anisotropy in Fe 2 Hf by Sb substitution, and illustrates the potential of (Fe,Sb) 2 + x Hf 1 − x Laves phase alloys for the permanent magnet applications.

Graphene-Based Sensors for Monitoring Strain

2013 ◽  
Vol 3 (1) ◽  
pp. 74-83
Author(s):  
M. Mirnezhad ◽  
R. Ansari ◽  
H. Rouhi ◽  
M. Faghihnasiri
Keyword(s):  
Fermi Level ◽  
Band Gap ◽  
Strain Distribution ◽  
Density Functional ◽  
Tight Binding ◽  
Density Functional Theory Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Gap Opening

The application of graphene as a nanosensor in measuring strain through its band structure around the Fermi level is investigated in this paper. The mechanical properties of graphene as well as its electronic structure are determined by using the density functional theory calculations within the framework of generalized gradient approximation. In the case of electronic properties, the simulations are applied for symmetrical and asymmetrical strain distributions in elastic range; also the tight-binding approach is implemented to verify the results. It is indicated that the energy band gap does not change with the symmetrical strain distribution but depend on the asymmetric strain distribution, increasing strain leads to band gap opening around the Fermi level.

Hydrogen Storage in MOF-5 with Fluorine Substitution: A van der Waals Density Functional Theory Study

2013 ◽  
Vol 716 ◽  
pp. 244-247 ◽  
Author(s):  
Yue Huang ◽  
San Huang Ke
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Storage ◽  
Density Functional ◽  
Van Der Waals ◽  
Functional Theory ◽  
Fluorine Substitution ◽  
Hydrogen Molecules ◽  
The Density Functional Theory ◽  
Metal Organic ◽  
Organic Linker

Physisorption of hydrogen molecules in metal-organic frameworks (MOFs) provides a promising way for hydrogen storage, in which the van der Waals (vdW) interaction plays an important role but cannot be described by the density functional theory (DFT). Using the vdW density functional (vdW-DF) method, we perform ab initio calculations for the MOF-5 crystal with one or multiple H2 adsorbed in its primitive cell. It is found that the binding with the organic linker is much smaller than with the metal oxide corner, which limits the H2 loading. We show that this can be improved significantly (from 5.50 to 10.39 kJ/mol) by replacing the H atoms of the organic linker with F atoms which causes extra electrostatic interaction.

An unusual CC⋯CO interaction in (Z)-3-[(4-halogenphenyl)amino]-2-cyanoprop-2-enoates

2016 ◽  
Vol 40 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Zhenfeng Zhang ◽  
Nana Ma ◽  
Xiaopeng Xuan
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
The Density Functional Theory

An unusual CC⋯CO interaction has been discovered in (Z)-3-[(4-halogenphenyl)amino]-2-cyanoprop-2-enoates and rationalized by the density functional theory calculations.

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