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 Surprisingly facile CO2 insertion into cobalt alkoxide bonds: A theoretical investigation

2015 ◽  
Vol 11 ◽  
pp. 1340-1351 ◽  
Author(s):  
Willem K Offermans ◽  
Claudia Bizzarri ◽  
Walter Leitner ◽  
Thomas E Müller
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Density Functional Theory ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Activation Barrier ◽  
Density Functional Theory Calculations ◽  
Reaction Energy ◽  
Reaction Step ◽  
Functional Theory

Exploiting carbon dioxide as co-monomer with epoxides in the production of polycarbonates is economically highly attractive. More effective catalysts for this reaction are intensively being sought. To promote better understanding of the catalytic pathways, this study uses density functional theory calculations to elucidate the reaction step of CO2 insertion into cobalt(III)–alkoxide bonds, which is also the central step of metal catalysed carboxylation reactions. It was found that CO2 insertion into the cobalt(III)–alkoxide bond of [(2-hydroxyethoxy)CoIII(salen)(L)] complexes (salen = N,N”-bis(salicyliden-1,6-diaminophenyl)) is exothermic, whereby the exothermicity depends on the trans-ligand L. The more electron-donating this ligand is, the more exothermic the insertion step is. Interestingly, we found that the activation barrier decreases with increasing exothermicity of the CO2 insertion. Hereby, a linear Brønsted–Evans–Polanyi relationship was found between the activation energy and the reaction energy.

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.

Theoretical study of CO2 hydrogenation into formic acid on Lewis acid zeolites

2018 ◽  
Vol 20 (39) ◽  
pp. 25179-25185 ◽  
Author(s):  
Worawaran Thongnuam ◽  
Thana Maihom ◽  
Saowapak Choomwattana ◽  
Yuwanda Injongkol ◽  
Bundet Boekfa ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Formic Acid ◽  
Density Functional ◽  
Theoretical Study ◽  
Co2 Hydrogenation ◽  
Functional Theory ◽  
Acid Zeolites ◽  
Acidic Zeolites ◽  
Hydrogenation Of Carbon Dioxide

The hydrogenation of carbon dioxide (CO2) to formic acid over Lewis acidic zeolites as catalyst has been investigated by means of density functional theory (DFT) with the M06-L functional.

scholarly journals Theoretical study on the reaction mechanism of “ligandless” Ni-catalyzed hydrodesulfurization of aryl sulfide

RSC Advances ◽  
2017 ◽  
Vol 7 (81) ◽  
pp. 51475-51484 ◽  
Author(s):  
Sheng Fang ◽  
Meiyan Wang ◽  
Jingjing Liu ◽  
Bingwen Li ◽  
Jing-yao Liu
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Theoretical Study ◽  
Reaction Pathways ◽  
Competitive Reaction ◽  
Functional Theory ◽  
Aryl Sulfide

The reaction mechanism of Ni(COD)2 catalyzed hydrodesulfurization of aryl sulfide PhSMe with HSiMe3 has been predicted to have two competitive reaction pathways, with or without PhSMe spectator ligand, by using density functional theory methods.

scholarly journals A computational study of the competing reaction mechanisms of the photo-catalytic reduction of CO2 on anatase(101)

2016 ◽  
Vol 18 (36) ◽  
pp. 25010-25021 ◽  
Author(s):  
Chung Man Ip ◽  
Alessandro Troisi
Keyword(s):  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Reaction Mechanisms ◽  
Density Functional ◽  
Catalytic Reduction ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
Reaction Pathways ◽  
Functional Theory ◽  
Reduction Of Co2

Three reaction pathways for the photocatalytic reduction of carbon dioxide to methane are investigated with density functional theory calculations.

Quantum Simulations of Preferable H2O Dissociation Pathway on the Ru-Alloyed Pt(111) Surface Based on Density Functional Theory

2020 ◽  
Vol 840 ◽  
pp. 495-500
Author(s):  
Victor Reynaldi ◽  
Wahyu Tri Cahyanto ◽  
Farzand Abdullatif
Keyword(s):  
Activation Energy ◽  
Density Functional Theory ◽  
Potential Energy Surfaces ◽  
Density Functional ◽  
Reaction Pathways ◽  
Dissociation Pathway ◽  
Reaction Route ◽  
Functional Theory ◽  
Energy Surfaces ◽  
Pes Scan

Reaction pathways for a water molecule dissociation (H2Oads) to form hydroxyl (OHads) and hydrogen (Hads) on the Ru-alloyed Pt(111) surface were computationally modelled on the basis of density functional theory (DFT). The aim of this study was to evaluate whether or not such a reaction can take place and to determine the most probable route for this reaction. To get the answer, we calculated the potential energy surfaces (PES) of the proposed reaction pathways. From the results of the PES scan, we then obtained the most preferential pathway for H2O dissociation, i.e., the reaction route with an activation energy of 0.72 eV. This activation energy value is lower than the value of pure Pt (111), the surface at which H2O dissociation can occur in the real system. Thus, it can be said that water splitting may be easier when catalyzing Ru-alloyed surfaces compared to pure Pt catalysts.

Theoretical Study on the Isomerization Reaction Mechanism of the Chain-Isomers of N9H9

2014 ◽  
Vol 887-888 ◽  
pp. 677-683
Author(s):  
Shu Zhang ◽  
Xiao Lan Wang ◽  
Wan Fei Cai ◽  
Lai Cai Li ◽  
An Min Tian
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Basis Set ◽  
Isomerization Reaction ◽  
Thermochemical Properties ◽  
Reaction Energy ◽  
Functional Theory ◽  
B3lyp Method ◽  
Isomerization Processes

Density functional theory B3LYP method with 6-311++G** basis set has been used to optimize Chain-isomers of N9H9. Sixteen species are found, the structures, stabilities, thermochemical properties, and their tautomerism are studied and discussed. The ten corresponding transition states have been found. The experimental results indicated that the reaction energy barriers of isomerization of these isomers were between 139.56 kJ/mol and 236.67kJ/mol. The activation energies is higher, the isomerization of these isomers is relatively difficult. The isomerization processes of these chain-isomers of N9H9 are all completed by the H transfer.

scholarly journals A Theoretical Study of the Hydrogenation of CO over Co2Cu2 Bimetallic Catalyst Supported on MgO(200) by Means of Density Functional Theory Part 2: Reaction Mechanism

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Nguyen Binh Long ◽  
Nguyen Thi Thu Ha ◽  
Phung Thi Lan ◽  
Le Minh Cam ◽  
Nguyen Ngoc Ha
Keyword(s):  
Activation Energy ◽  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Bimetallic Catalyst ◽  
Elastic Band ◽  
Functional Theory ◽  
Co Insertion ◽  
Insertion Process ◽  
Hydrogenation Of Carbon Monoxide

This paper investigates the hydrogenation of carbon monoxide (CO) over Co2Cu2 bimetallic catalyst supported on MgO (200) using a combination of density functional theory (DFT) and a climbing image nudged elastic band (CI-NEB) module. In the study, a reaction mechanism for the formation of methane, methanol and ethanol was proposed. The proposed mechanism consisted of 28 reaction steps (per surface type) and three different reaction positions were included. Reaction energy and activation energy for the overall steps involved in the reaction process were calculated and analyzed. The results show that the CoCu mixed sites reduced the activation energy of the CO insertion process into CH3, resulting in the formation of products with a larger number of carbon atoms.

scholarly journals Study on the Adsorption and Activation Behaviours of Carbon Dioxide over Copper Cluster (Cu4) and Alumina-Supported Copper Catalyst (Cu4/Al2O3) by means of Density Functional Theory

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Nguyen Thi Thu Ha ◽  
Van Thi Minh Hue ◽  
Bui Cong Trinh ◽  
Nguyen Ngoc Ha ◽  
Le Minh Cam
Keyword(s):  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Interaction ◽  
Copper Catalyst ◽  
Copper Cluster ◽  
Elastic Band ◽  
Alumina Support ◽  
Functional Theory ◽  
Catalytic Systems

The adsorption and activation of carbon dioxide over copper cluster (Cu4) and copper doped on the alumina support (Cu4/Al2O3) catalytic systems have been investigated by using density functional theory and climbing image nudged elastic band. The adsorption energies, geometrical configurations, and electronic properties are analysed. The results show the strong chemical interaction between the copper cluster and the alumina support. Both the Cu4 cluster and Cu4/Al2O3 systems have a high adsorption ability for CO2, and the adsorption process is of chemical nature. The role of the alumina support in the adsorption and activation of CO2 has been addressed. The calculated results show that the “synergistic effect” between Al2O3 and Cu4 is the key factor in the activation of CO2.

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