scholarly journals p-CuO/n-ZnO Heterojunction Structure for the Selective Detection of Hydrogen Sulphide and Sulphur Dioxide Gases: A Theoretical Approach

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1200
Author(s):  
Hasan Albargi ◽  
Hussein Y. Ammar ◽  
Heba M. Badran ◽  
Hassan Algadi ◽  
Ahmad Umar
Keyword(s):  
Dft Calculations ◽  
Recovery Time ◽  
Atomic Charges ◽  
Selective Detection ◽  
Heterojunction Structure ◽  
Sensing Applications ◽  
Response Recovery ◽  
Adsorption Energies ◽  
Homo Lumo ◽  
So2 Gas

DFT calculations at the B3LYP/LanL2DZ level of theory were utilized to investigate the adsorption of H2S and SO2 gases on the electronic properties of CuO-ZnO heterojunction structures. The results were demonstrated from the standpoint of adsorption energies (Eads), the density of states (DOS), and NBO atomic charges. The obtained values of the adsorption energies indicated the chemisorption of the investigated gases on CuO-ZnO heterojunction. The adsorption of H2S and SO2 gases reduced the HOMO-LUMO gap in the Cu2Zn10O12 cluster by 4.98% and 43.02%, respectively. This reveals that the Cu2Zn10O12 cluster is more sensitive to the H2S gas than the SO2 gas. The Eads values for SO2 and H2S were −2.64 and −1.58 eV, respectively. Therefore, the Cu2Zn10O12 cluster exhibits a higher and faster response-recovery time to H2S than SO2. Accordingly, our results revealed that CuO-ZnO heterojunction structures are promising candidates for H2S- and SO2-sensing applications.

CH2O Adsorption on M (M = Li, Mg and Al) Atom Deposited ZnO Nano-Cage: DFT Study

2018 ◽  
Vol 786 ◽  
pp. 384-392 ◽  
Author(s):  
Hussein Y. Ammar
Keyword(s):  
Density Functional Theory ◽  
Bond Length ◽  
Density Functional ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structural And Electronic Properties ◽  
Formaldehyde Molecule ◽  
Electronic Configurations ◽  
Adsorption Energies ◽  
Homo Lumo

The structural and electronic properties of Li, Mg and Al deposited ZnO nanocages and their effects on the adsorption of formaldehyde molecule have been investigated using the density functional theory (DFT) computations. To understand the behavior of the adsorbed CH2O molecule on the ZnO nanocage, results of DFT calculations of the M-deposited nanocages (M=Li, Mg and Al), as well as complex systems consisting of the adsorbed CH2O molecule on M-deposited ZnO nanocage were reported. The results presented include adsorption energies, bond lengths, electronic configurations, density of states and molecular orbitals. It was found that, the most energetically stable adsorption configurations of CH2O molecule on the bare ZnO leads to 12% dilation in C=O bond length of CH2O and 14% decrease in HOMO-LUMO gap of ZnO cluster. The most energetically stable adsorption configurations of CH2O molecule on Li, Mg and Al-deposited ZnO lead to 4%, 4% and 11% dilation in C=O bond length of CH2O and-0.66, -45 and , +66% change in HOMO-LUMO gap of ZnO nanocages, respectively. The interaction between CH2O with bare ZnO and M-deposited ZnO nanocages is attributed to charge transfer mechanism. These results may be meaningful for CH2O degradation and detection.

scholarly journals 5-Methyl-1,3-phenylene bis[5-(dimethylamino)naphthalene-1-sulfonate]: crystal structure and DFT calculations

2019 ◽  
Vol 75 (7) ◽  
pp. 1079-1083
Author(s):  
Tanwawan Duangthongyou ◽  
Ramida Rattanakam ◽  
Kittipong Chainok ◽  
Songwut Suramitr ◽  
Thawatchai Tuntulani ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Energy Gap ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Hydrogen Atoms ◽  
Lumo Energy ◽  
Compound C ◽  
Dansyl Group ◽  
Weak Hydrogen Bonds ◽  
Homo Lumo

The title compound, C31H30N2S2O6, possesses crystallographically imposed twofold symmetry with the two C atoms of the central benzene ring and the C atom of its methyl substituent lying on the twofold rotation axis. The two dansyl groups are twisted away from the plane of methylphenyl bridging unit in opposite directions. The three-dimensional arrangement in the crystal is mainly stabilized by weak hydrogen bonds between the sulfonyl oxygen atoms and the hydrogen atoms from the N-methyl groups. Stacking of the dansyl group is not observed. From the DFT calculations, the HOMO–LUMO energy gap was found to be 2.99 eV and indicates n→π* and π→π* transitions within the molecule.

scholarly journals Hydroquinone–pyrrole dyads with varied linkers

2016 ◽  
Vol 12 ◽  
pp. 89-96 ◽  
Author(s):  
Hao Huang ◽  
Christoffer Karlsson ◽  
Maria Strømme ◽  
Martin Sjödin ◽  
Adolf Gogoll
Keyword(s):  
Dft Calculations ◽  
Electrical Energy ◽  
Energy Storage Devices ◽  
Active Materials ◽  
Electrical Energy Storage ◽  
Storage Devices ◽  
H Nmr ◽  
Redox Active ◽  
Homo Lumo ◽  
C Nmr

A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices.

Synthesis of CuO–CdS composite nanowires and their ultrasensitive ethanol sensing properties

2019 ◽  
Vol 6 (1) ◽  
pp. 238-247 ◽  
Author(s):  
Nan Zhang ◽  
Xiaohui Ma ◽  
Yanyang Yin ◽  
Yu Chen ◽  
Chuannan Li ◽  
...  
Keyword(s):  
Recovery Time ◽  
Solvothermal Method ◽  
Operating Temperature ◽  
Average Diameter ◽  
One Dimension ◽  
Sensing Properties ◽  
Response Recovery ◽  
Ethanol Sensing

One dimension CuO/CdS composites with an average diameter of 30 nm were synthesized by a solvothermal method. The operating temperature of the sensors is 182 °C, and their responses were improved by 6 times. The ultrafast response–recovery time was obtained.

An ab initio study of sensing applications of MoB2 monolayer: a potential gas sensor

2019 ◽  
Vol 21 (8) ◽  
pp. 4633-4640 ◽  
Author(s):  
Amreen Bano ◽  
Jyoti Krishna ◽  
Devendra K. Pandey ◽  
N. K. Gaur
Keyword(s):  
Ab Initio ◽  
Gas Sensor ◽  
Recovery Time ◽  
Ab Initio Study ◽  
Fast Recovery ◽  
Sensing Applications

Theoretically studied MoB2 monolayer detects NO2 gas with fast recovery time.

scholarly journals Atomic, electronic and magnetic structure of an oxygen interstitial in neutron-irradiated Al2O3 single crystals

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
V. Seeman ◽  
A. Lushchik ◽  
E. Shablonin ◽  
G. Prieditis ◽  
D. Gryaznov ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Single Crystals ◽  
Density Functional ◽  
Magnetic Moments ◽  
Atomic Charges ◽  
Interstitial Oxygen ◽  
Absorption Bands ◽  
Magnetic Field Rotation ◽  
Formal Charge ◽  
Radiation Induced

Abstract A single radiation-induced superoxide ion $$O_{2}^{ - }$$ O 2 - has been observed for the first time in metal oxides. This structural defect has been revealed in fast-neutron-irradiated (6.9×1018n/cm2) corundum (α-Al2O3) single crystals using the EPR method. Based on the angular dependence of the EPR lines at the magnetic field rotation in different planes and the determined g tensor components, it is shown that this hole-type $$O_{2}^{ - }$$ O 2 - center (i) incorporates one regular and one interstitial oxygen atoms being stabilized by a trapped hole (S = 1/2), (ii) occupies one oxygen site in the (0001) plane being oriented along the a axis, and (iii) does not contain any other imperfection/defect in its immediate vicinity. The thermal stepwise annealing (observed via the EPR signal and corresponding optical absorption bands) of the $$O_{2}^{ - }$$ O 2 - centers, caused by their destruction with release of a mobile ion (tentatively the oxygen ion with the formal charge −1), occurs at 500–750 K, simultaneously with the partial decay of single F-type centers (mostly with the EPR-active F+ centers). The obtained experimental results are in line with the superoxide defect configurations obtained via density functional theory (DFT) calculations employing the hybrid B3PW exchange-correlation functional. In particular, the DFT calculations confirm the $$O_{2}^{ - }$$ O 2 - center spin S = 1/2, its orientation along the a axis. The $$O_{2}^{ - }$$ O 2 - center is characterized by a short O–O bond length of 1.34 Å and different atomic charges and magnetic moments of the two oxygens. We emphasize the important role of atomic charges and magnetic moments analysis in order to identify the ground state configuration.

Molecular structure, Vibrational assignment, HOMO-LUMO and Mulliken analysis of 2-[4-amino-2-(4-methylphenylamino) thiazol-5-oyl]benzothiazole(AMPATOB)

2016 ◽  
Vol 2 (1) ◽  
pp. 38
Author(s):  
Dr A Yardily
Keyword(s):  
Molecular Structure ◽  
Mass Spectra ◽  
Density Functional ◽  
Dft Method ◽  
Dihedral Angles ◽  
Atomic Charges ◽  
Vibrational Assignment ◽  
Functional Theory ◽  
Wave Numbers ◽  
Homo Lumo

The compound 2-[4-amino-2-(4-methylphenylamino) thiazol-5-oyl]benzothiazole (AMPATOB) was prepared from 1-(4-methylphenyl)-3-(N-nitroamidino)thiourea and 2-(2-bromoacetyl)benzothiazole in the presence of triethylamine and characterised  by FTIR, NMR and mass spectra. The geometry of the molecule was investigated and optimized with the help of B3LYP/ 6-31G density functional theory (DFT) method using Gaussian 09 software package.The calculated geometries such as bond lengths, bond angles, dihedral angles, atomic charges, harmonic vibrational wave numbers and intensities of vibrational bonds of the titled compound were investigated. The experimental 1H NMR and IR spectrum was compared with theoretical value. The molecule consists of three ring systems, all are lying in one plane.

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