scholarly journals A theoretical study on the CO2 methanation over Ni5/AC catalysts by means of density functional theory. Part I: Adsorption and activation stages

2020 ◽  
Vol 9 (1) ◽  
pp. 33-38
Author(s):  
Hue Van Thi Minh ◽  
Lan Phung Thi ◽  
Ha Nguyen Thi Thu ◽  
Cam Le Minh ◽  
Ha Nguyen Ngoc
Keyword(s):  
Density Functional Theory ◽  
Activated Carbon ◽  
Adsorption Energy ◽  
Density Functional ◽  
Adsorption Process ◽  
Theoretical Study ◽  
Bond Orders ◽  
Elastic Band ◽  
Co2 Methanation ◽  
Functional Theory

The adsorption and activation processes of CO2 and H2 on Ni5 catalyst supported on activated carbon (Ni5/AC) were investigated by using density functional theory at GGA-PBE/DZP level of theory and climbing image – nudged elastic band (CI-NEB) method. The adsorption energy, charges on atoms, bond orders and geometry parameters were calculated and analyzed. The most favourable adsorption configurations were determined. The results show that H2 and CO2 are chemically adsorbed on Ni5/AC. The adsorption process does not involved a transition state. CO2 is strongly activated on Ni5/AC system.

scholarly journals A theoretical study on the CO2 methanation over Ni5/AC catalysts by means of density functional theory. Part II: Reaction pathways

2020 ◽  
Vol 9 (1) ◽  
pp. 73-80
Author(s):  
Hue Van Thi Minh ◽  
Lan Phung Thi ◽  
Ha Nguyen Thi Thu ◽  
Cam Le Minh ◽  
Ha Nguyen Ngoc
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Reaction Pathways ◽  
Reaction Energy ◽  
Elastic Band ◽  
Co2 Methanation ◽  
Functional Theory

The methanation of carbon dioxide over Ni5 supported on activated carbon (Ni5/AC) was studied by using density functional theory and climbing image – nudged elastic band methods. A reaction diagram for the formation of methane via CO or HCOO species, which consists of 14 reaction steps was proposed. The reaction energy and activation energy for the overall steps involved in the reaction process were calculated and analyzed. Following the proposed mechanism possible carbon byproducts of the CO2 methanation reaction are CO and HCHO. Formation of these products can occur at high temperatures, but it is more thermodynamically difficult than formation of CH4. The formation of CH4 is more preferably occur via the CO pathway than the HCOO pathway.

scholarly journals A Theoretical Study on the Hydrogenation of CO Over Co2Cu2 Bimetallic Catalyst Supported on MgO(200) by Means of Density Functional Theory Part 1: Adsorption and Activation Stages

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Nguyen Binh Long ◽  
Nguyen Thi Thu Ha ◽  
Phung Thi Lan ◽  
Le Minh Cam ◽  
Nguyen Ngoc Ha
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Adsorption Process ◽  
Theoretical Study ◽  
Bimetallic Catalyst ◽  
Functional Theory ◽  
Initial Cluster ◽  
Mgo Support ◽  
Adsorption Processes ◽  
Hydrogenation Of Co

Density functional theory (DFT) at GGA-PBE/DZP level was performed to study the adsorption processes of CO and H2 on clusters Co2Cu2 and Co2Cu2 supported on MgO (Co2Cu2/MgO) system. The electronic structures, geometries of Co2Cu2 and Co2Cu2/MgO, adsorption energies were studied and analyzed. The optimal adsorption configurations of CO and H2 on Co2Cu2 and Co2Cu2/MgO were determined. The results show that CO and H2 are chemically adsorbed on Co2Cu2 and Co2Cu2/MgO systems and the adsorption process does not involve a transition state. MgO support plays important role in the increasing of the activation ability of Co2Cu2/MgO for CO compared to the initial cluster. Keywords: Syngas, DFT, Co2Cu2, MgO, adsorption.  

A theoretical study on solvatofluorochromic asymmetric thiazolothiazole (TTz) dyes using dielectric-dependent density functional theory

2021 ◽  
Vol 23 (37) ◽  
pp. 21078-21086
Author(s):  
Tomomi Shimazaki ◽  
Masanori Tachikawa
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Dye Molecules ◽  
Excitation Energies ◽  
Functional Theory ◽  
Dependent Density

In this work, the excitation energies of asymmetric thiazolothizaole (TTz) dye molecules have been theoretically studied using dielectric-dependent density functional theory (DFT).

A Theoretical Study of H2S Toxic Gas Adsorption on Pristine and Doped Monolayer (AlN)21 Using Density Functional Theory

2020 ◽  
Vol 12 (02) ◽  
pp. 99-111
Author(s):  
Jamal A. Shlaka ◽  
◽  
Abbas H. Abo Nasria
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Gas Adsorption ◽  
Aluminium Nitride ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Gas Molecules ◽  
Toxic Gas ◽  
Center Ring

Been studying the interactions between graphene - like aluminium nitride P(AlN)21 nano ribbons doped and defect (AlN)21Sheet, Molecules and small toxic gas molecules ( H2S), were built for two different adsorption sites on graphene like aluminium nitride P(AlN)21. this was done by employing B3LYP density functional theory (DFT) with 6-31G*(d,p) using Gaussian 09 program, Gaussian viw5.0 package of programs and Nanotube Modeller program 2018. the adsorptions of H2S on P(AlN)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C)atoms-doped P(AL-N)19 (on atom) with (Ead) (-0.468eV),(-0.473 eV), (-0.457 eV), (-0.4478 eV) and (-0.454 eV), respectively, (Ead) of H2S on the center ring of the P(AL-N)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C,B)atoms-doped P(AL-N)19 sheet are (-0.280 eV),(-0.465 eV), (-0.405 eV), (-0.468 eV) and -0.282 eV), respectively, are weak physisorption . However, the adsorptions of H2S, on the ((AlN)20 -B and D- (AlN)19 -B), (on atom N and center ring the sheet) are a strong chemisorption because of the (Ead) larger than -0.5 eV, due to the strong interaction, the ((AlN)20-B and D-(AlN)19-B), could catalyst or activate, through the results that we obtained, which are the improvement of the sheet P(AlN)21 by doping and per forming a defect in, it that can be used to design sensors. DOI: http://dx.doi.org/10.31257/2018/JKP/2020/120210

Meso-alkynyl corroles and their cobalt(III), manganese(III) and gallium(III) complexes

2020 ◽  
Vol 24 (05n07) ◽  
pp. 737-749
Author(s):  
Michael Haas ◽  
Sabrina Gonglach ◽  
Wolfgang Schöfberger
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Study ◽  
Lumo Energy ◽  
Functional Theory ◽  
Energy Gaps ◽  
Peak Broadening ◽  
Homo And Lumo ◽  
Homo Lumo

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.

scholarly journals Theoretical Study on Influence of Cobalt Oxides Valence State Change for C6H5COOH Pyrolysis

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 197
Author(s):  
Si-Mei Fu ◽  
Yue Zhao ◽  
Jiang-Tao Liu ◽  
Wen-Sheng Liang ◽  
Gang-Sen Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Valence State ◽  
Energy Barrier ◽  
Density Functional ◽  
Model Compound ◽  
Theoretical Study ◽  
Cobalt Oxides ◽  
State Change ◽  
Pyrolysis Process ◽  
Functional Theory

Benzoic acid (C6H5COOH) is selected as coal-based model compound with Co compounds (Co3O4, CoO and Co) as the catalysts, and the influence of the valence state change of the catalyst for pyrolysis process is investigated using density functional theory (DFT). DFT results shows that the highest energy barrier of C6H5COOH pyrolysis is in the following order: Ea(CoO) <Ea(Co3O4) <Ea(no catalyst) <Ea(Co). In general, Co3O4 catalyst accelerates C6H5COOH pyrolysis. Then, the catalytic activity further increases when Co3O4 is reduced to CoO. Finally, Co shows no activity for C6H5COOH pyrolysis due to the reduction of CoO to metallic Co.

Sign in / Sign up

Export Citation Format

Share Document