Kinetics and Thermodynamics of CO Oxidation by (TiO2)6

Molecular level insights into the mechanism and thermodynamics of CO oxidation by a (TiO2)6 cluster have been obtained through density functional calculations. Thereby, in this study, as an example, two different structural isomers of (TiO2)6 are considered with the purpose of understanding the interplay between local structure and activity for the CO oxidation reaction. Active sites in the two isomeric forms were identified on the basis of global and local reactivity descriptors. For the oxidation of CO to CO2, the study considered both sequential and simultaneous adsorption of CO and O2 on (TiO2)6 cluster through the ER and LH mechanisms, respectively. Three different pathways were obtained for CO oxidation by (TiO2)6 cluster, and the mechanistic route of each pathway were identified by locating the transition-state and intermediate structures. The effect of temperature on the rate of the reaction was investigated within the harmonic approximation. The structure-dependent activity of the cluster was rationalized through reactivity descriptors and analysis of the frontier orbitals.

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Kinetics and Thermodynamics of CO Oxidation by (TiO2)6

10.22541/au.161243970.07303869/v1 ◽

2021 ◽

Author(s):

Navjot Kaur ◽

Neetu Goel ◽

Michael Springborg ◽

Mohammad Molayem

Keyword(s):

Co Oxidation ◽

Active Sites ◽

Density Functional ◽

Harmonic Approximation ◽

Oxidation Mechanism ◽

Structural Isomers ◽

Reactivity Descriptors ◽

Co Oxidation Reaction ◽

Adsorption Of Co ◽

Global And Local

Molecular level insights into the mechanism and thermodynamics of CO oxidation by a (TiO) cluster have been obtained through density functional calculations. Thereby, we have considered as an example, two different structural isomers of (TiO) with the purpose of understanding the interplay between local structure and activity for the CO oxidation reaction. Active sites in the two isomeric forms were identified on the basis of global and local reactivity descriptors. For the oxidation of CO to CO2 we considered both sequential and simultaneous adsorption of CO and O2 on (TiO2)6 cluster through the ER and LH mechanisms, respectively. Three different pathways were obtained for CO oxidation by (TiO2)6 cluster, and the mechanistic route of each pathway were identified by locating the transition-state and intermediate structures. The effects of temperature on the rate of the reaction was investigated within the harmonic approximation. The structure-dependent activity of the cluster was rationalized through reactivity descriptors and analysis of the frontier orbitals. Finally, we also considered the effects of a support, i.e., graphene, on the oxidation mechanism.

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Calculation of the Global and Local Conceptual DFT Indices for the Prediction of the Chemical Reactivity Properties of Papuamides A–F Marine Drugs

Molecules ◽

10.3390/molecules24183312 ◽

2019 ◽

Vol 24 (18) ◽

pp. 3312 ◽

Cited By ~ 2

Author(s):

Norma Flores-Holguín ◽

Juan Frau ◽

Daniel Glossman-Mitnik

Keyword(s):

Density Functional Theory ◽

Active Sites ◽

Density Functional ◽

Chemical Reactivity ◽

Active Regions ◽

Conceptual Density Functional Theory ◽

Functional Theory ◽

Reactivity Descriptors ◽

Global And Local

A well-behaved model chemistry previously validated for the study of the chemical reactivity of peptides was considered for the calculation of the molecular properties and structures of the Papuamide family of marine peptides. A methodology based on Conceptual Density Functional Theory (CDFT) was chosen for the determination of the reactivity descriptors. The molecular active sites were associated with the active regions of the molecules related to the nucleophilic and electrophilic Parr functions. Finally, the drug-likenesses and the bioactivity scores for the Papuamide peptides were predicted through a homology methodology relating them with the calculated reactivity descriptors, while other properties such as the pKas were determined following a methodology developed by our group.

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Spectroscopic investigations and DFT studies of synthesized 4-acetamidophenyl 3,4,5-trimethoxybenzoate and 4-acetyl phenyl 3,4,5-trimethoxybenzoate a novel conjugate of gallic acid

Letters in Organic Chemistry ◽

10.2174/1570178617999200818205347 ◽

2020 ◽

Vol 17 ◽

Author(s):

Sangeeta Srivastava ◽

Nadeem Ahmad Ansari ◽

Sadaf Aleem

Keyword(s):

Gallic Acid ◽

Density Functional ◽

Energy Gap ◽

Basis Set ◽

Major Constituent ◽

Orbital Energy ◽

Reactivity Descriptors ◽

Homo And Lumo ◽

Electrophilic Reactivity ◽

Global And Local

: Gallic acid is abundantly found in amla (Phyllanthus emblica), a deciduous of the family phyllanthaceae. Gallic acid, the major constituent of the plant was methylated to 3,4,5 trimethoxy gallic acid, which then underwent steglich esterification first with paracetamol and then with 4-hydroxy acetophenone to yield 4-acetamidophenyl 3,4,5-trimethoxybenzoate and 4-acetyl phenyl 3,4,5-trimethoxybenzoate “respectively”. 1H NMR, 13C NMR, UV, FT-IR and mass spectroscopy were used to characterize the synthesized compounds. Density functional theory (B3YLP) using 6-31G (d,p) basis set have been used for quantum chemical calculations. AIM (Atom in molecule) approach depicted weak molecular interactions within the molecules whereas the reactive site and reactivity within the molecule were examined by global and local reactivity descriptors. The HOMO and LUMO energies and frontier orbital energy gap were calculated by time dependant DFT approach using IEFPCM model. Small value for HOMO–LUMO energy gap indicated that easier charge transfer occurs within compound 4. The nucleophilic and electrophilic reactivity were determined by MEP (molecular electrostatic potential) experiment. Polarizability, dipole moment, and first hyperpolarizability values were calculated to depict the NLO (nonlinear optical) property of both the synthesized compounds. The antimicrobial activity was also carried out and broad spectrum antibacterial activity against several strains of bacteria and certain unicellular fungi were exhibited by synthesized compound 3.

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Study on adsorption of CO and CO2 by graphene gas sensor

Modern Physics Letters B ◽

10.1142/s0217984921501542 ◽

2021 ◽

pp. 2150154

Author(s):

Wenchao Tian ◽

Jiahao Niu ◽

Wenhua Li ◽

Xiaohan Liu

Keyword(s):

Gas Sensors ◽

Active Sites ◽

Density Functional ◽

Gas Adsorption ◽

Experimental Studies ◽

Detection Accuracy ◽

Functional Theory ◽

Vacancy Defects ◽

Adsorption Of Co ◽

Detection Characteristics

The two-dimensional (2D) plane of graphene has many active sites for gas adsorption. It has broad application prospects in the field of MEMS gas sensors. At present, there are many experimental studies on graphene gas sensors, but it is difficult to accurately control various influencing factors in the experiments. Therefore, this paper applies the first principle based on density functional theory to study the adsorption and detection characteristics of graphene on CO and CO2. The first-principles analysis method was used to study the adsorption characteristics and sensitivity of graphene. The results show that the inductive graphene has a sensitivity of 1.55% and 0.77% for CO and CO2, respectively. The Stone–Wales defects and multi-vacancy defects have greatly improved the sensitivity of graphene to CO, which is 35.25% and 4.14%, respectively. Introduction of defects increases the sensitivity of detection of CO and CO2, but also improves the selective gas detection material of these two gases. Thus, the control and selectively introducing defects may improve the detection accuracy of the graphene CO and CO2.

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Assessment of the KID Procedure on a Mo–oxo Complex, an Open–Shell System

10.20944/preprints202007.0742.v1 ◽

2020 ◽

Author(s):

Jorge Martínez-Araya ◽

Daniel Glossman-Mitnik

Keyword(s):

Density Functional ◽

Organic Molecules ◽

Open Shell ◽

Density Functionals ◽

Functional Theory ◽

Reactivity Descriptors ◽

Shell System ◽

Global And Local ◽

First Time ◽

Local Reactivity Descriptors

The KID (Koopmans in DFT) procedure usually applies in organic molecules of the closed–shell type. We used the KID procedure in an open–shell system for the first time to choose the most suitable density functional to compute global and local reactivity descriptors coming from the Conceptual Density–Functional Theory. From a set of 18 density functionals spread from the second until the fourth rung of the Jacob’s ladder: BP86, B97-D, BLYP, CAM-B3LYP, M06-L, M11-L, MN12-L, B3LYP, PBE0, N12-SX, M06-2X, M11, MN12-SX, CAM-B3LYP, LC-ωHPBE, ωB97X-D, APFD, MN15 and MN15-L, we concluded that CAM-B3LYP provides the best outcome.

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Density functional study on the CO oxidation reaction mechanism on MnN2-doped graphene

RSC Advances ◽

10.1039/d0ra05287f ◽

2020 ◽

Vol 10 (46) ◽

pp. 27856-27863

Author(s):

Mingming Luo ◽

Zhao Liang ◽

Chao Liu ◽

Xiaopeng Qi ◽

Mingwei Chen ◽

...

Keyword(s):

Reaction Mechanism ◽

Co Oxidation ◽

Oxidation Reaction ◽

Density Functional ◽

Functional Study ◽

Density Functional Study ◽

Co Oxidation Reaction ◽

Doped Graphene ◽

First Time

The various COOR mechanisms on MnN2-doped graphene (MnN2C2: MnN2C2-hex, MnN2C2-opp, MnN2C2-pen) were investigated for the first time.

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CO oxidation catalysed by Pd-based bimetallic nanoalloys

Physical Chemistry Chemical Physics ◽

10.1039/c5cp00889a ◽

2015 ◽

Vol 17 (42) ◽

pp. 28010-28021 ◽

Cited By ~ 18

Author(s):

Dennis Palagin ◽

Jonathan P. K. Doye

Keyword(s):

Density Functional Theory ◽

Co Oxidation ◽

Oxidation Reaction ◽

Density Functional ◽

Geometry Optimization ◽

Energy Barriers ◽

Functional Theory ◽

Global Geometry ◽

Co Oxidation Reaction

Density functional theory based global geometry optimization has been used to demonstrate the crucial influence of the geometry of the catalytic cluster on the energy barriers for the CO oxidation reaction over Pd-based bimetallic nanoalloys.

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Conceptual DFT-based Computational Peptidology of Marine Natural Compounds: Discodermins A–H

10.20944/preprints202008.0351.v1 ◽

2020 ◽

Author(s):

Norma Flores-Holguín ◽

Juan Frau ◽

Daniel Glossman-Mitnik

Keyword(s):

Density Functional Theory ◽

Active Sites ◽

Density Functional ◽

Homology Model ◽

Conceptual Density Functional Theory ◽

Functional Theory ◽

Fukui Functions ◽

Reactivity Descriptors ◽

Qsar Studies ◽

Biological Targets

A methodology based on the concepts that arise from Density Functional Theory named Conceptual Density Functional Theory (CDFT) was chosen for the calculation of some global and local reactivity descriptors of the Discodermins A-H family of marine peptides through the consideration of the KID (Koopmans in DFT) technique that was successfully used in previous studies of this kind of molecular systems. The determination of active sites of the studied molecules for different kind of reactivities was achieved by resorting to some CDFT-based descriptors like the Fukui functions as well as the Parr functions derived from Molecular Electron Density Theory (MEDT). A few properties identified with their ability to behave as a drug and the bioactivity of the peptides considered in this examination were acquired by depending on a homology model by studying the correlation with the known bioactivity of related molecules in their interaction with various biological receptors. With the further object of analyzing their bioactivity some parameters of usefulness for future QSAR studies, their predicted biological targets and the the ADME (Absorption, Distribution, Metabolism, and Excretion) parameters related to the Discodermins A-H pharmacokinetics are also reported.

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Exploring the Relationship between the CO Oxidation Reaction and the Elemental Composition in Electrocatalysts with Machine Learning - a Case Study of PtRuPdRhAu High Entropy Alloys

10.33774/chemrxiv-2021-zpbqb-v3 ◽

2021 ◽

Author(s):

Vladislav Mints ◽

Jack Pedersen ◽

Alexander Bagger ◽

Jonathan Quinson ◽

Andy Anker ◽

...

Keyword(s):

Machine Learning ◽

Co Oxidation ◽

Oxidation Reaction ◽

Density Functional ◽

Hydrogen Oxidation ◽

Bayesian Optimization ◽

High Entropy Alloy ◽

Onset Potential ◽

High Entropy ◽

Co Oxidation Reaction

In recent years, the development of complex multi-metallic nanomaterials like high entropy alloy (HEA) catalysts has gained popularity. Composed of 5 or more metals, the compositions of HEAs exhibit extreme diversity. This is both a promising avenue to identify new catalysts and a severe constraint on their preparation and study. To address the challenges related to the preparation, study and optimization of HEAs, machine learning solutions are attractive. In this paper, the composition of PtRuPdRhAu hydrogen oxidation catalysts is optimized for the CO oxidation reaction. This is achieved by constructing a dataset using Bayesian optimization as guidance. For this quinary nanomaterial, the best performing composition was found within the first 35 experiments. However, the dataset was expanded until a total of 68 samples were investigated. This final dataset was used to construct a random forest regression model and a linear model. These machine learned models were used to assess the relationships between the concentrations of the consituent elements and the CO oxidation reaction onset potential. The onset potentials were found to correlate with the composition dependent adsorption energy of *OH obtained from density functional theory. This study demonstrates, how machine learning can be employed in an experimental setting to investigate the vast compositional space of HEAs.

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