Ti-coated BC2N nanotubes as hydrogen storage materials

2013 ◽  
Vol 91 (7) ◽  
pp. 598-604 ◽  
Author(s):  
Seifollah Jalili ◽  
Farzad Molani ◽  
Jeremy Schofield
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Molecular Form ◽  
Hydrogen Storage Materials ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Hydrogen Molecules ◽  
Bc2n Nanotubes

Density functional theory (DFT) calculations have been performed to investigate Ti adsorption on BC2N nanotubes and the hydrogen adsorption capacity of Ti-coated structures. Different adsorption sites have been examined for the Ti adatom, and it is found that the most stable structure has a configuration with alternating columns of carbon and boron–nitrogen hexagons. The DFT calculations indicate that an adsorbed Ti atom on a carbon hexagon can bind four hydrogen molecules in molecular form, while Ti atoms on boron–nitride hexagons can adsorb three hydrogen molecules and two hydrogen atoms. Based on the calculations, the gravimetric efficiency corresponding to decoration of 67% of six carbon rings with Ti adatoms is estimated to be 8 wt %. Computation of the charge transfer reveals that the Ti atom on BC2N is in a cationic state. In addition, Ti adsorption has a significant influence on the electronic structure of the nanotubes and allows for the conversion of nanotubes from semiconductors in the pristine state to conductors upon doping. The interactions between the nanotubes, the Ti atom and hydrogen molecules have also been analyzed using Dewar coordination and Kubas interactions.

Investigation, using density function theory, of coverage of the kaolinite (001) surface during hydrogen adsorption

Clay Minerals ◽  
2018 ◽  
Vol 53 (3) ◽  
pp. 393-402 ◽  
Author(s):  
Jian Zhao ◽  
Wei Gao ◽  
Zhi-Gang Tao ◽  
Hong-Yun Guo ◽  
Man-Chao He
Keyword(s):  
Density Functional ◽  
Hydrogen Adsorption ◽  
Function Theory ◽  
Lattice Relaxation ◽  
Electronic Density ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Coverage Dependence ◽  
Hydrogen Molecules ◽  
Wide Range

ABSTRACTKaolinite can be used for many applications, including the underground storage of gases. Density functional theory was employed to investigate the adsorption of hydrogen molecules on the kaolinite (001) surface. The coverage dependence of the adsorption sites and energetics was studied systematically for a wide range of coverage, Θ (from 1/16 to 1 monolayer). The three-fold hollow site is the most stable, followed by the bridge, top-z and top sites. The adsorption energy of H2 decreased with increasing coverage, thus indicating the lower stability of surface adsorption due to the repulsion of neighbouring H2 molecules. The coverage has obvious effects on hydrogen adsorption. Other properties of the H2/kaolinite (001) system, including the lattice relaxation and changes of electronic density of states, were also studied and are discussed in detail.

scholarly journals Density-Functional Theory Study of Hydrogen Induced Platelets in Silicon

2011 ◽  
Vol 1370 ◽  
Author(s):  
Liviu Bîlteanu ◽  
Jean-Paul Crocombette
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Stable Configuration ◽  
Density Functional Theory Study ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Hydrogen Molecules ◽  
The One ◽  
Infinite Planar

ABSTRACTIn this contribution we present the results of Density-Functional Theory (DFT) calculations of platelets as modelled by infinite planar arrangements of hydrogen atoms and vacancies in (100) planes of silicon. From the observation of the relaxed platelet structures and the comparison of their energy with the one of hydrogen molecules dissolved in silicon we were able to evidence several features. A planar arrangement of hydrogen atoms inserted in the middle of Si-Si bonds proves unstable and Si bonds must be broken for the platelet to be stable. In the (100) plane the most stable configuration is the one with two Si-H bonds (a so-called SiH2 structure). It is possible to generate SiH3 structures which are more stable than hydrogen dissolved in Si bulk but less than SiH2 structures but SiH1 or SiH4 sometimes observed in experiments prove unstable.

scholarly journals The dynamics of benzene on Cu(111): a combined helium spin echo and dispersion-corrected DFT study into the diffusion of physisorbed aromatics on metal surfaces

2017 ◽  
Vol 204 ◽  
pp. 471-485 ◽  
Author(s):  
M. Sacchi ◽  
P. Singh ◽  
D. M. Chisnall ◽  
D. J. Ward ◽  
A. P. Jardine ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Spin Echo ◽  
Metallic Surface ◽  
Bravais Lattice ◽  
Binding Interaction ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Lattice Density ◽  
Shed Light

We use helium spin-echo spectroscopy (HeSE) to investigate the dynamics of the diffusion of benzene adsorbed on Cu(111). The results of these measurements show that benzene moves on the surface through an activated jump-diffusion process between the adsorption sites on a Bravais lattice. Density Functional Theory (DFT) calculations with van der Waals (vdW) corrections help us understand that the molecule diffuses by jumping through non-degenerate hollow sites. The results of the calculations shed light on the nature of the binding interaction between this prototypical aromatic molecule and the metallic surface. The highly accurate HeSE experimental data provide a quantitatively stringent benchmark for the vdW correction schemes applied to the DFT calculations and we compare the performances of several dispersion interaction schemes.

scholarly journals A First-Principles Study on Titanium-Decorated Adsorbent for Hydrogen Storage

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6845
Author(s):  
Kai Ma ◽  
Erfei Lv ◽  
Di Zheng ◽  
Weichun Cui ◽  
Shuai Dong ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculation ◽  
Partial Density ◽  
Ambient Conditions ◽  
Functional Theory ◽  
Hydrogen Molecules ◽  
Theory Calculation ◽  
Hydrogen Storage Medium

Based on density functional theory calculation, we screened suitable Ti-decorated carbon-based hydrogen adsorbent structures. The adsorption characteristics and adsorption mechanism of hydrogen molecules on the adsorbent were also discussed. The results indicated that Ti-decorated double vacancy (2 × 2) graphene cells seem to be an efficient material for hydrogen storage. Ti atoms are stably embedded on the double vacancy sites above and below the graphene plane, with binding energy higher than the cohesive energy of Ti. For both sides of Ti-decorated double vacancy graphene, up to six H2 molecules can be adsorbed around each Ti atom when the adsorption energy per molecule is −0.25 eV/H2, and the gravimetric hydrogen storage capacity is 6.67 wt.%. Partial density of states (PDOS) analysis showed that orbital hybridization occurs between the d orbital of the adsorbed Ti atom and p orbital of C atom in the graphene layer, while the bonding process is not obvious during hydrogen adsorption. We expect that Ti-decorated double vacancy graphene can be considered as a potential hydrogen storage medium under ambient conditions.

scholarly journals Density Functional Theory Study of Hydrogen Electroadsorption on the Pt(110) surfaces

2017 ◽  
Vol 20 (K2) ◽  
pp. 77-83
Author(s):  
Hanh Thi Thu Tran
Keyword(s):  
Total Energy ◽  
Density Functional ◽  
Lattice Gas ◽  
Hydrogen Adsorption ◽  
Simulated Data ◽  
Energy Calculation ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Electrode Surfaces ◽  
Unit Cells

The hydrogen adsorption on the Pt(110) and Pt(110)-(1x2) electrode surfaces has been investigated. To gain insight into detailed atomistic picture on the equilibrium coverage and structure, we have constructed a lattice gas model by determining the on-site energy and the interaction parameters using the first principles total-energy calculation. Therein atop, fcc, short bridge, long bridge and R, T, F, F’ sites for H/Pt(110) and H/Pt(110)-(1x2) are covered by hydrogen atoms under various coverage conditions 0 ML < θ < 1 ML and the total-energy calculations are done for the (1x1) and (1x2) cells. The surface of (1×2) and (1×1) lateral unit cells. The convergence property with respect to the number of Pt layers and the k-point mesh are found. The comparison between different surface types are done. By comparing the calculated results with two different theoretical simulated data, SIESTA and VASP, we found good agreement between them.

scholarly journals Insight into anomalous hydrogen adsorption on rare earth metal decorated on 2-dimensional hexagonal boron nitride: a density functional theory study

RSC Advances ◽  
2020 ◽  
Vol 10 (22) ◽  
pp. 12929-12940
Author(s):  
Shreeja Das ◽  
Saroj K. Nayak ◽  
Kisor K. Sahu
Keyword(s):  
Rare Earth ◽  
Boron Nitride ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Hexagonal Boron Nitride ◽  
Earth Metal ◽  
Functional Theory ◽  
Hydrogen Molecules ◽  
Strong Adsorption ◽  
Insight Into

The central rare earth cerium atom and underlying apolar B–N bonds in two-dimensional hexagonal boron nitride facilitate a unique arrangement of hydrogen molecules which leads to fairly strong adsorption of eight hydrogen molecules per metal atom.

Understanding the Mechanism of Hydrogen Adsorption into Metal-Organic Frameworks

2005 ◽  
Vol 885 ◽  
Author(s):  
Tae-Bum Lee ◽  
Daejin Kim ◽  
Seung-Hoon Choi ◽  
Ji Hye Yoon ◽  
Sang Beom Choi ◽  
...  
Keyword(s):  
Benzene Ring ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculation ◽  
Metal Organic Frameworks ◽  
Geometry Optimization ◽  
Porous Metal ◽  
Adsorption Sites ◽  
Hydrogen Molecules ◽  
Metal Organic

ABSTRACTHydrogen adsorption mechanism into the porous metal-organic frameworks (MOFs) has been studied by density functional theory calculation. The selected functionals for the prediction of interaction energies between hydrogen and potential adsorption sites of MOFs were utilized after the evaluation with the various functionals for interaction energy of H2···C6H6 model system. The adsorption energy of hydrogen molecule into MOFs was investigated with the consideration of the favorable adsorption sites and the orientations. We also calculated the second favorable adsorption sites by geometry optimization using every combination of two first absorbed hydrogen molecules. Based on the calculation of first and second adsorption sites and energies, it has been suggested that the hydrogen adsorption into MOFs follows a cooperative mechanism in which the initial metal sites initiate the propagation of the hydrogen adsorption on the whole frameworks. In addition, the interaction mode between the simple benzene ring with hydrogen is significantly changed when the benzene ring has been incorporated into the framework of MOFs.

scholarly journals Study of the Effect of Absorbed Cu Species on the Surface of Specularite (0 0 1) by the DFT Calculations

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 930
Author(s):  
Mingzhu Huangfu ◽  
Jiaxin Li ◽  
Xi Zhang ◽  
Yiming Hu ◽  
Jiushuai Deng ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Activation Mechanism ◽  
Partial Density ◽  
Adsorption Model ◽  
Activation Effect ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Fe Complexes ◽  
Species Being

Cu2+ exhibited a good activation effect on specularite. However, its microscopic activation mechanism needs further study. Additionally, Cu2+ was mainly present in the flotation solution as Cu2+, Cu(OH)+, and Cu(OH)2 at pH = 7. Therefore, density functional theory (DFT) calculations were used to investigate the effect of Cu species such as Cu2+, Cu(OH)+, and Cu(OH)2 adsorbed on the crystal structure and properties of the specularite (0 0 1) surface. The adsorption mechanism of different Cu components on the surface was also further clarified by the analyses of the adsorption model, adsorption energy, partial density of states (PDOS), charge transfer, and bond properties. In addition, the obtained results are discussed. Based on the obtained results, it can be concluded that the geometric structure and electronic properties on the surface changed after adsorbing Cu components and that the O3–Fe1–O1 structure was more susceptible to the adsorbates. The adsorption engines results show that Cu components could be spontaneously adsorbed onto the specularite (0 0 1) surface with adsorption energies of −0.76, −0.85, and −1.78 eV, corresponding to Cu2+, CuOH+, and Cu(OH)2, respectively. Therefore, the adsorption stability of the Cu species on the specularite surface increased in the order of Cu2+ < Cu(OH)+ < Cu(OH)2. Additionally, the adsorption sites for Cu species on the surface were different. Cu2+ interacted mainly with O atoms on the surface, forming Cu–O complexes, while Cu(OH)+ and Cu(OH)2 acted mainly through the O atom of –OH, interacting with Fe atoms to form Cu–O–Fe complexes. The formation of Cu–O and Cu–O–Fe complexes increased the adsorption sites for sodium oleate, with more hydrophobic species being generated to improve the floatability of specularite.

scholarly journals Density Functional Theory Study of Hydrogen Adsorption on Pt Pd/γ-Al2O3 Surface

2021 ◽  
Vol 2097 (1) ◽  
pp. 012020
Author(s):  
Liang Zhang ◽  
Jia Li ◽  
Yong Chen ◽  
Cheng Zeng ◽  
Wu Kang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Energy Gap ◽  
Solid Catalyst ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Lower Energy Level ◽  
Catalytic Hydrogen

Abstract At present passive hydrogen recombiners (PAR) are used to prevent hydrogen explosion. Hydrogen removal catalyst is the core component of PAR. The adsorption of hydrogen on the solid catalyst surface is the premise of catalytic hydrogen removal and is of great significance for deeper understanding of hydrogen removal mechanism. The adsorption behavior of H2-Pt Pd/γ-Al2O3 system has been studied by using density functional theory and periodic slab model. The results of different adsorption sites indicate the adsorption energy of top site is highest, which is -1.2584eV. Higher adsorption energy means stronger interaction between H2 and catalyst substrate, which elongates H-H bond and increases the negative charge on H2. With increasing doping content of Pd, the adsorption energy of substrate decreases gradually. The adsorption energy absolute value of Pt4/γ-Al2O3 is highest and its H-H bond is longest, arriving at 0.0967nm. After adsorbed on substrate, the energy gap of H2 decreases drastically with the lowest energy gap of H2-Pt4/γ-Al2O3 that is 0.5197eV, and the peaks of density of state pattern move to lower energy level. This is because that the d orbital of Pt/Pd atoms interacts with the τ* anti-bond orbital of H2 strongly, transferring electrons to the τ* anti-bond orbital of H2. Doping Pd increases the energy gap of molecule orbital.

Adsorption Forms of Water Molecules on Gas-Phase Platinum Clusters Pt3+ Studied by Vibrational Photodissociation Spectroscopy

2019 ◽  
Vol 233 (6) ◽  
pp. 881-894 ◽  
Author(s):  
Fumitaka Mafuné ◽  
Manami Abe ◽  
Satoshi Kudoh
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Gas Phase ◽  
Vibrational Spectra ◽  
Density Functional ◽  
Molecular Form ◽  
Vibrational Excitation ◽  
Water Molecules ◽  
Functional Theory ◽  
Platinum Clusters

Abstract The vibrational spectra of Pt3(H2O)m+ (m = 1–4) cluster were measured in the 3000–3800 cm−1 range via infrared photodissociation (IRPD) spectroscopy. The IRPD spectra were recorded through the photodissociation of Pt3(H2O)m+-Ar (m = 1–3) complexes and Pt3(H2O)4+ cations upon vibrational excitation. The spectra were compared to the vibrational spectra of several stable isomers obtained by density functional theory (DFT) calculations and the adsorption forms of the water molecules were subsequently discussed. The IRPD spectra of all the studied Pt3(H2O)m+ cations exhibited intense peaks at ∼3600 and 3700 cm−1. This suggested that the water molecules mainly adsorb onto the Pt clusters in molecular form and that each molecule binds directly to a Pt atom via its O atom side. For the water-rich Pt3(H2O)4+ cations, all four water molecules were directly bound to the Pt atoms; however, according to the DFT calculations, the fourth H2O molecule could bind to a first-layer water molecule through hydrogen bonding.

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