Theoretical Investigation of H2 Interactions on ZnO Cluster: DFT Approach

2018 ◽  
Vol 17 (03) ◽  
pp. 1760041 ◽  
Author(s):  
A. Aruna Devi ◽  
S. Vidya ◽  
P. K. Rai ◽  
B. G. Jeyaprakash
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Energy Gap ◽  
Computational Study ◽  
Mulliken Charge ◽  
Intrinsic Reaction Coordinate ◽  
Adsorption Sites ◽  
Dissociation Mechanisms ◽  
Adsorption And Dissociation

A computational study on adsorption and dissociation mechanisms of H2 molecule on ZnO cluster was analysed using Density Functional Theory (DFT) approach in Gaussian 09 software. The stable sites for hydrogen adsorption were inferred from the adsorption energy and bond length. Further investigations such as Mulliken charge, HOMO–LUMO energy gap and intrinsic reaction coordinate (IRC) were performed for the stable adsorption sites. It infers that the (ZnO)6 cluster has the highest binding energy of 1.851[Formula: see text]eV (O-site) and the least binding energy of [Formula: see text]3.865[Formula: see text]eV (O-site), showing most favorable size for both adsorption and dissociation of H2 molecule. The IRC plot clearly shows the dissociation mechanism of hydrogen on the ZnO cluster.

scholarly journals Physi-Sorption of H2 on Pure and Boron–Doped Graphene Monolayers: A Dispersion–Corrected DFT Study

2020 ◽  
Vol 6 (1) ◽  
pp. 15 ◽  
Author(s):  
Iffat Nayyar ◽  
Bojana Ginovska ◽  
Abhijeet Karkamkar ◽  
Thomas Gennett ◽  
Thomas Autrey
Keyword(s):  
Binding Energy ◽  
Binding Sites ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
High Surface ◽  
High Surface Area ◽  
Direct Interaction ◽  
Boron Doping ◽  
Adsorption Sites ◽  
Boron Doped

High-surface-area carbons are of interest as potential candidates to store H2 for fuel–cell power applications. Earlier work has been ambiguous and inconclusive on the effect of boron doping on H2 binding energy. Here, we describe a systematic dispersion–corrected density functional theory study to evaluate the effect of boron doping. We observe some enhancement in H2 binding, due to the presence of a defect, such as terminal hydrogen or distortion from planarity, introduced by the inclusion of boron into a graphene ring, which creates hydrogen adsorption sites with slightly increased binding energy. The increase is from −5 kJ/mol H2 for the pure carbon matrix to −7 kJ/mol H2 for the boron–doped system with the boron content of ~7%. The H2 binding sites have little direct interaction with boron. However, the largest enhancement in physi-sorption energy is seen for systems, where H2 is confined between layers at a distance of about 7 Å, where the H2 binding nearly doubles to −11 kJ/mol H2. These findings suggest that interplanar nanoconfinement might be more effective in enhancing H2 binding. Smaller coronene model is shown to be beneficial for understanding the dependence of interaction energy on the structural configurations and preferential H2 binding sites.

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.

A Computational Study of Catalytic Platinum Nanoparticles With and Without OH Chemisorption During Reactions

2008 ◽  
Author(s):  
Mikhail Sekachev ◽  
Cheng-Xian Lin ◽  
Zhiyu Hu ◽  
Don Dareing
Keyword(s):  
Binding Energy ◽  
Total Energy ◽  
Platinum Nanoparticles ◽  
Cluster Size ◽  
Density Functional ◽  
Energy Gap ◽  
Computational Study ◽  
Basis Set ◽  
Functional Theory ◽  
The Stability

In this paper, various energies and geometries of pure platinum nanoparticles and those of platinum nanoparticles with adsorbed OH were investigated. Ten different platinum clusters of up to 28 atoms were studied using spin-unrestricted density functional theory (DFT) with a double numerical plus polarization basis set. Three different shapes were presented, and the effect of cluster size on binding energy, total energy, and HOMO-LUMO energy gap was investigated. The same set of calculations was performed for selected clusters with OH adsorbate on the Pt(111) surface. The results show that the stability of both the pure clusters and the clusters with adsorbed OH molecule increases with an increase of cluster size. This fact indicates that direct influence of the size of Pt cluster on the reaction rate is possible, and the understanding of how cluster size would affect binding energy is important. The effect of cluster size on total energy of molecule was shown to be a linear function independent of cluster type, as expected. We also found that optimized (stable) Pt clusters were bigger in size than that of the initial clusters, or clusters with bulk geometry.

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 Synthesis, X-Ray Crystallography, Thermal Analysis, and DFT Studies of Ni(II) Complex with 1-Vinylimidazole Ligand

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Fatih Şen ◽  
Ramazan Şahin ◽  
Muharrem Dinçer ◽  
Ömer Andaç ◽  
Murat Taş
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Basis Sets ◽  
Mulliken Charge ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Dft Methods ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Density Functional Theory

The paper presents a combined experimental and computational study of hexa(1-vinylimidazole)Ni(II) perchlorate complex. The complex was prepared in the laboratory and crystallized in the monoclinic space group P21/n with a=8.442(5), b=13.686(8), c=16.041(9) Å, α=γ=90, β=96.638(5), and Z=1. The complex has been characterized structurally (by single-crystal X-Ray diffraction) and its molecular structure in the ground state has been calculated using the density functional theory (DFT) methods with 6-31G(d) and LanL2DZ basis sets. Thermal behaviour and stability of the complex were studied by TGA/DTA analyses. Besides, the nonlinear optical effects (NLO), molecular electrostatic potential (MEP), frontier molecular orbitals (FMO), and the Mulliken charge distribution were investigated theoretically.

scholarly journals Computational mechanistic study of the unimolecular dissociation of ethyl hydroperoxide and its bimolecular reactions with atmospheric species

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mansour H. Almatarneh ◽  
Asmaa Alnajajrah ◽  
Mohammednoor Altarawneh ◽  
Yuming Zhao ◽  
Mohammad A. Halim
Keyword(s):  
Activation Energy ◽  
Density Functional ◽  
Computational Study ◽  
Basis Sets ◽  
Mechanistic Study ◽  
Intrinsic Reaction Coordinate ◽  
Unimolecular Dissociation ◽  
Phase Reaction ◽  
Atmospheric Species ◽  
Solvation Models

Abstract A detailed computational study of the atmospheric reaction of the simplest Criegee intermediate CH2OO with methane has been performed using the density functional theory (DFT) method and high-level calculations. Solvation models were utilized to address the effect of water molecules on prominent reaction steps and their associated energies. The structures of all proposed mechanisms were optimized using B3LYP functional with several basis sets: 6-31G(d), 6-31G (2df,p), 6-311++G(3df,3pd) and at M06-2X/6-31G(d) and APFD/6-31G(d) levels of theory. Furthermore, all structures were optimized at the B3LYP/6-311++G(3df,3pd) level of theory. The intrinsic reaction coordinate (IRC) analysis was performed for characterizing the transition states on the potential energy surfaces. Fifteen different mechanistic pathways were studied for the reaction of Criegee intermediate with methane. Both thermodynamic functions (ΔH and ΔG), and activation parameters (activation energies Ea, enthalpies of activation ΔHǂ, and Gibbs energies of activation ΔGǂ) were calculated for all pathways investigated. The individual mechanisms for pathways A1, A2, B1, and B2, comprise two key steps: (i) the formation of ethyl hydroperoxide (EHP) accompanying with the hydrogen transfer from the alkanes to the terminal oxygen atom of CIs, and (ii) a following unimolecular dissociation of EHP. Pathways from C1 → H1 involve the bimolecular reaction of EHP with different atmospheric species. The photochemical reaction of methane with EHP (pathway E1) was found to be the most plausible reaction mechanism, exhibiting an overall activation energy of 7 kJ mol−1, which was estimated in vacuum at the B3LYP/6-311++G(3df,3pd) level of theory. All of the reactions were found to be strongly exothermic, expect the case of the sulfur dioxide-involved pathway that is predicted to be endothermic. The solvent effect plays an important role in the reaction of EHP with ammonia (pathway F1). Compared with the gas phase reaction, the overall activation energy for the solution phase reaction is decreased by 162 and 140 kJ mol−1 according to calculations done with the SMD and PCM solvation models, respectively.

Preferred Hydrogen Adsorption Sites in Various MOFs-A Comparative Computational Study

ChemPhysChem ◽  
2009 ◽  
Vol 10 (15) ◽  
pp. 2647-2657 ◽  
Author(s):  
Michael Fischer ◽  
Frank Hoffmann ◽  
Michael Fröba
Keyword(s):  
Hydrogen Adsorption ◽  
Computational Study ◽  
Adsorption Sites

Density Functional Study on the Configurations of Nen (n=2~36) Clusters

2017 ◽  
Vol 727 ◽  
pp. 381-387
Author(s):  
Chang Ning Peng ◽  
Xing Rong Zheng
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Energy Gap ◽  
Geometry Optimization ◽  
Basis Set ◽  
Functional Study ◽  
B3lyp Method ◽  
The Density Functional Theory ◽  
Quantum Chemistry Calculations ◽  
Average Bond

Based on the First-principles and the method of quantum chemistry calculations, using the B3LYP method and 6-31G basis set of the density functional theory (DFT), the configurations and binding energy of Nen (n=2~36) clusters are calculated and studied theoretically after the calculation of geometry optimization. By changing the atomic number n of the Nen (n=2~36) clusters, it obtained that the stable structures, the binding energy and HOMO - LUMO energy gap of the Nen (n=2~36) clusters under the same ideal conditions, and summarizes the change rule of the stable configurations, the binding energy and the average bond length of the Nen (n=2~36) clusters.

First principles study of the adsorption and dissociation mechanisms of H2S on a TiO2anatase (001) surface

RSC Advances ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 7941-7949 ◽  
Author(s):  
Naeem Shahzad ◽  
Akhtar Hussain ◽  
Naeem Mustafa ◽  
Nisar Ali ◽  
Mohammed Benali Kanoun ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculation ◽  
Functional Theory ◽  
P Adsorption ◽  
First Principles Study ◽  
The Density Functional Theory ◽  
Dissociation Mechanisms ◽  
Adsorption And Dissociation

Adsorption and dissociation mechanisms of H2S on a TiO2(001) surface were elucidated using first principles calculation based on the density functional theory.

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