scholarly journals DFT Simulation of the Water Molecule Interaction with the (00l) Surface of Montmorillonite

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 501
Author(s):  
Gianfranco Ulian ◽  
Daniele Moro ◽  
Giovanni Valdrè
Keyword(s):  
Water Molecule ◽  
Environmental Remediation ◽  
Density Functional ◽  
Building Materials ◽  
Chemical Properties ◽  
Food Science ◽  
Functional Theory ◽  
Physico Chemical ◽  
Molecule Interaction ◽  
Mineralogical Phases

Montmorillonite is one of the principal mineralogical phases in clay minerals, where its interaction with water and other molecules represents one of the most important aspects and properties for basic science and specific applications. In fact, montmorillonite has many uses in various scientific and technological fields, ranging from environmental remediation to ceramics, food science, and construction/building materials. Several efforts have characterized its structure and physico-chemical properties, especially at the Tetrahedral-Octahedral-Tetrahedral TOT surface. For this purpose, in this work, the authors investigated the structural and electrostatic potential features of the (00l) surface of montmorillonite and the water adsorption process by first principle methods (density functional theory, DFT), considering both static and molecular dynamics approaches. The provided data further extend the knowledge of the modulation of the water molecule adsorption with this important clay mineral.

scholarly journals Electrocatalytic hydrogen evolution on the noble metal-free MoS2/carbon nanotube heterostructure: a theoretical study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farhad Keivanimehr ◽  
Sajjad Habibzadeh ◽  
Alireza Baghban ◽  
Amin Esmaeili ◽  
Ahmad Mohaddespour ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Noble Metal ◽  
Electrocatalytic Activity ◽  
Density Functional ◽  
Minimum Energy ◽  
Chemical Properties ◽  
Binding Energies ◽  
Functional Theory ◽  
Metal Free ◽  
Physico Chemical

AbstractMolybdenum disulfide (MoS2) is considered as a promising noble-metal-free electrocatalyst for the Hydrogen Evolution Reaction (HER). However, to effectively employ such material in the HER process, the corresponding electrocatalytic activity should be comparable or even higher than that of Pt-based materials. Thus, efforts in structural design of MoS2 electrocatalyst should be taken to enhance the respective physico-chemical properties, particularly, the electronic properties. Indeed, no report has yet appeared about the possibility of an HER electrocatalytic association between the MoS2 and carbon nanotubes (CNT). Hence, this paper investigates the synergistic electrocatalytic activity of MoS2/ CNT heterostructure for HER by Density Functional Theory simulations. The characteristics of the heterostructure, including density of states, binding energies, charge transfer, bandgap structure and minimum-energy path for the HER process were discussed. It was found that regardless of its configuration, CNT is bound to MoS2 with an atomic interlayer gap of 3.37 Å and binding energy of 0.467 eV per carbon atom, suggesting a weak interaction between CNT and MoS2. In addition, the energy barrier of HER process was calculated lower in MoS2/CNT, 0.024 eV, than in the MoS2 monolayer, 0.067 eV. Thus, the study elaborately predicts that the proposed heterostructure improves the intrinsic electrocatalytic activity of MoS2.

Computational Study of Au Doped Cu Nano Alloy Clusters

2017 ◽  
Vol 17 ◽  
pp. 62-71 ◽  
Author(s):  
Prabhat Ranjan ◽  
Tanmoy Chakraborty ◽  
Ajay Kumar
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Chemical Properties ◽  
Alternation Behavior ◽  
Functional Theory ◽  
Bimetallic Nanoclusters ◽  
Physico Chemical ◽  
Properties Of Materials ◽  
Alloy Clusters ◽  
Homo Lumo

Among several bimetallic nanoclusters, the compounds formed between Cu-Au have gained immense importance due to its remarkable optical, mechanical, electronic and catalytic behaviors. Density Functional Theory (DFT) is one of the most successful and popular approaches of quantum mechanics to explore electronic properties of materials. Conceptual DFT based descriptors have become indispensable tools for analyzing and correlating the experimental properties of compounds. In this venture, we have successfully investigated the physico-chemical properties of Au doped Cu nanoclusters invoking DFT methodology. Our results reveal that computed HOMO-LUMO gap of CunAu (n=1-7) nanoalloy clusters show pronounced even-odd alternation behavior. A close agreement between experimental and our computed data is observed.

Organics on oxidic metal surfaces: a first-principles DFT study of PMDA and ODA fragments on the pristine and mildly oxidized surfaces of Cu(111)

2016 ◽  
Vol 18 (31) ◽  
pp. 21893-21902 ◽  
Author(s):  
Jong-Hun Park ◽  
Ji-Hwan Lee ◽  
Aloysius Soon
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Chemical Properties ◽  
Density Functional Theory Calculations ◽  
Metal Substrate ◽  
Mild Oxidation ◽  
Molecular Fragments ◽  
Functional Theory ◽  
Physico Chemical

Using van der Waals corrected density-functional theory calculations, we study the fundamental physico-chemical properties of the molecular fragments of pyromellitic dianhydride oxydianiline (PMDA–ODA) on pristine and oxidized Cu(111) to investigate the effect of mild oxidation of the metal substrate on PMDA–ODA adsorption.

Computational Investigation of Cationic, Anionic and Neutral Ag2AuN (N = 1–7) Nanoalloy Clusters

2017 ◽  
Vol 2 (10) ◽  
Author(s):  
Prabhat Ranjan ◽  
Tanmoy Chakraborty ◽  
Ajay Kumar
Keyword(s):  
Ground State ◽  
Density Functional ◽  
Close Agreement ◽  
Chemical Properties ◽  
Computational Investigation ◽  
Science And Engineering ◽  
Functional Theory ◽  
Physico Chemical ◽  
Properties Of Materials ◽  
Theoretical Insight

AbstractThe study of bimetallic nanoalloy clusters is of immense importance due to their diverse applications in the field of science and engineering. A deep theoretical insight is required to explain the physico-chemical properties of such compounds. Among such nanoalloy clusters, the compound formed between Ag and Au has received a lot of attention because of their marked electronic, catalytic, optical and magnetic properties. Density Functional Theory (DFT) is one of the most successful approaches of quantum mechanics to study the electronic properties of materials. Conceptual DFT-based descriptors have turned to be indispensable tools for analysing and correlating the experimental properties of compounds. In this report, we have investigated the ground state configurations and physico-chemical properties of Ag2AuNλ(N= 1–7,λ=±1, 0) nanoalloy clusters invoking DFT methodology. Our computed data exhibits interesting odd-even oscillation behaviour. A close agreement between experimental and our computed bond length supports our theoretical analysis.

Investigation of 1,2,3-trialkylimidazolium ionic liquids: experiment and density functional theory calculations

2017 ◽  
Vol 41 (2) ◽  
pp. 650-660 ◽  
Author(s):  
Snežana Papović ◽  
Milan Vraneš ◽  
Stevan Armaković ◽  
Sanja J. Armaković ◽  
Katalin Mészáros Szécsényi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Density Functional Theory ◽  
Ionic Liquids ◽  
Thermogravimetric Analysis ◽  
Density Functional ◽  
Chemical Properties ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Density Measurements ◽  
Physico Chemical

Physico-chemical properties, thermal stability and bonding in 1,2,3-trialkylimidazolium based ionic liquids (ILs) were investigated by viscosity and density measurements together with thermogravimetric analysis (TGA) and IR spectroscopy.

The Nature of S-N Bonding in Sulfonamides and Related Compounds: Insights into π-Bonding Contributions from Sulfur K-Edge XAS

2020 ◽  
Author(s):  
Tulin Okbinoglu ◽  
Pierre Kennepohl
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Functional Theory ◽  
Rotational Barriers ◽  
Td Dft ◽  
Nitrogen Bonds ◽  
X Ray Absorption ◽  
Related Compounds ◽  
And Chemical Properties

Molecules containing sulfur-nitrogen bonds, like sulfonamides, have long been of interest due to their many uses and chemical properties. Understanding the factors that cause sulfonamide reactivity is important, yet their continues to be controversy regarding the relevance of S-N π bonding in describing these species. In this paper, we use sulfur K-edge x-ray absorption spectroscopy (XAS) in conjunction with density functional theory (DFT) to explore the role of S<sub>3p</sub> contributions to π-bonding in sulfonamides, sulfinamides and sulfenamides. We explore the nature of electron distribution of the sulfur atom and its nearest neighbors and extend the scope to explore the effects on rotational barriers along the sulfur-nitrogen axis. The experimental XAS data together with TD-DFT calculations confirm that sulfonamides, and the other sulfinated amides in this series, have essentially no S-N π bonding involving S<sub>3p</sub> contributions and that electron repulsion and is the dominant force that affect rotational barriers.

DFT study on the hydrolysis of metsulfuron-methyl: A sulfonylurea herbicide

2018 ◽  
Vol 17 (08) ◽  
pp. 1850050 ◽  
Author(s):  
Qiuhan Luo ◽  
Gang Li ◽  
Junping Xiao ◽  
Chunhui Yin ◽  
Yahui He ◽  
...  
Keyword(s):  
Free Energy ◽  
Water Molecule ◽  
Carbonyl Group ◽  
Energy Barrier ◽  
Density Functional ◽  
Free Energy Barrier ◽  
Functional Theory ◽  
Metsulfuron Methyl ◽  
Catalytic Role ◽  
Hydrolysis Of

Sulfonylureas are an important group of herbicides widely used for a range of weeds and grasses control particularly in cereals. However, some of them tend to persist for years in environments. Hydrolysis is the primary pathway for their degradation. To understand the hydrolysis behavior of sulfonylurea herbicides, the hydrolysis mechanism of metsulfuron-methyl, a typical sulfonylurea, was investigated using density functional theory (DFT) at the B3LYP/6-31[Formula: see text]G(d,p) level. The hydrolysis of metsulfuron-methyl resembles nucleophilic substitution by a water molecule attacking the carbonyl group from aryl side (pathway a) or from heterocycle side (pathway b). In the direct hydrolysis, the carbonyl group is directly attacked by one water molecule to form benzene sulfonamide or heterocyclic amine; the free energy barrier is about 52–58[Formula: see text]kcal[Formula: see text]mol[Formula: see text]. In the autocatalytic hydrolysis, with the second water molecule acting as a catalyst, the free energy barrier, which is about 43–45[Formula: see text]kcal[Formula: see text]mol[Formula: see text], is remarkably reduced by about 11[Formula: see text]kcal[Formula: see text]mol[Formula: see text]. It is obvious that water molecules play a significant catalytic role during the hydrolysis of sulfonylureas.

scholarly journals AVALIAÇÃO DA ESTRUTURA ELETRÔNICA DA FASE MONOCLINICA DO ÓXIDO DE NIÓBIO COM BASE NO USO DE DIFERENTES FUNCIONAIS DE DENSIDADE

Química Nova ◽  
2021 ◽  
Author(s):  
Kamila Ody ◽  
João Jesus ◽  
Carlos Cava ◽  
Anderson Albuquerque ◽  
Ary Maia ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Density Functionals ◽  
Monoclinic Structure ◽  
Functional Theory ◽  
Periodic Models ◽  
Physical And Chemical ◽  
And Chemical Properties

ASSESSMENT OF THE ELECTRONIC STRUCTURE OF THE MONOCLINIC PHASE OF NIOBIUM OXIDE BASED ON THE USE OF DIFFERENT DENSITY FUNCTIONALS. Niobium oxides, Nb2O5, are considered semiconductor materials with very attractive physical and chemical properties for applications in many areas, such as catalysis, sensors, medical, aerospace, etc. Especially, the characterization of Nb2O5-based nanostructures with monoclinic structure has received much attention in recent years. However, despite the great importance of this system, some of its fundamentals properties are still not fully understood. Hence, this work aims to apply the theoretical methodologies through Density Functional Theory (DFT) calculations in periodic models based on the use of different density functionals (like B1WC, B3PW, B3LYP, PBE0, PBESOL0, SOGGAXC, and WC1LYP) to investigate the physical and chemical properties of the monoclinic structure of Nb2O5. The band structures, energy bandgap, density of state, and vibrational properties, as well as order-disorder effects on the monoclinic structure of Nb2O5 are investigated in this study. Our theoretical results show a better agreement with experimental data for the B3LYP functional and hence lead to new perspectives on the deeper physicochemical understanding of the monoclinic Nb2O5. From these computational tools, it is possible to unravel the relations between structure and properties, which may contribute to the future development of new devices and applications based on these materials.

scholarly journals Computational Evidence Suggests That 1-chloroethanol May Be an Intermediate in the Thermal Decomposition of 2-chloroethanol into Acetaldehyde and HCl

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Oscar Ventura ◽  
Vincenzo Barone
Keyword(s):  
Aqueous Solution ◽  
Water Molecule ◽  
Gas Phase ◽  
Density Functional ◽  
Water Molecules ◽  
Functional Theory ◽  
Direct Transformation ◽  
The Density Functional Theory ◽  
Successive Step ◽  
The One

<p>The dehalogenation of 2-chloroethanol (2ClEtOH) in gas phase with and without participation of catalytic water molecules has been investigated using methods rooted into the density functional theory. The well-known HCl elimination leading to vinyl alcohol (VA) was compared to the alternative elimination route towards oxirane and shown to be kinetically and thermodynamically more favorable. However, the isomerization of VA to acetaldehyde in the gas phase, in the absence of water, was shown to be kinetically and thermodynamically less favorable than the recombination of VA and HCl to form the isomeric 1-chloroethanol (1ClEtOH) species. This species is more stable than 2ClEtOH by about 6 kcal mol<sup>-1</sup>, and the reaction barrier is 22 kcal mol<sup>-1</sup> vs 55 kcal mol<sup>-1</sup> for the direct transformation of VA to acetaldehyde. In a successive step, 1ClEtOH can decompose directly to acetaldehyde and HCl with a lower barrier (29 kcal mol<sup>-1</sup>) than that of VA to the same products (55 kcal mol<sup>-1</sup>). The calculations were repeated using a single ancillary water molecule (W) in the complexes 2ClEtOH_W and 1ClEtOH_W. The latter adduct is now more stable than 2ClEtOH_W by about 8 kcal mol<sup>-1</sup>, implying that the water molecule increased the already higher stability of 1ClEtOH in the gas phase. However, this catalytic water molecule lowers dramatically the barrier for the interconversion of VA to acetaldehyde (from 55 to 6 kcal mol<sup>-1</sup>). This barrier is now smaller than the one for the conversion to 1ClEtOH (which also decreases, but not so much, from 22 to 12 kcal mol<sup>-1</sup>). Thus, it is concluded that while 1ClEtOH may be a plausible intermediate in the gas phase dehalogenation of 2ClEtOH, it is unlikely that it plays a major role in water complexes (or, by inference, aqueous solution). It is also shown that neither in the gas phase nor in the cluster with one water molecule, the oxirane path is competitive with the VA alcohol path.</p>

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