Kinetic understanding of the effect of Na and Mg on pyrolytic behavior of lignin using a distributed activation energy model and density functional theory modeling

2019 ◽  
Vol 21 (5) ◽  
pp. 1099-1107 ◽  
Author(s):  
Kwang Ho Kim ◽  
Keunhong Jeong ◽  
Seung-Soo Kim ◽  
Robert C. Brown
Keyword(s):  
Activation Energy ◽  
Density Functional Theory ◽  
Density Functional ◽  
Alkaline Earth ◽  
Catalytic Effect ◽  
Energy Model ◽  
Alkaline Earth Metals ◽  
Distributed Activation Energy Model ◽  
Functional Theory ◽  
Naturally Occurring

The catalytic effect of Na and Mg, naturally occurring alkali and alkaline earth metals, on lignin pyrolysis was systematically analyzed using a distributed activation energy model and computational modeling.

Catalytic Effect of Alkali and Alkaline Earth Metals in Lignin Pyrolysis: A Density Functional Theory Study

2020 ◽  
Vol 34 (8) ◽  
pp. 9734-9740 ◽  
Author(s):  
Keunhong Jeong ◽  
Hye Jin Jeong ◽  
Gunwoo Lee ◽  
Sang Hoon Kim ◽  
Kwang Ho Kim ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Alkaline Earth ◽  
Catalytic Effect ◽  
Alkaline Earth Metals ◽  
Density Functional Theory Study ◽  
Functional Theory

scholarly journals Crossover from metal to insulator in dense lithium-rich compound CLi4

2016 ◽  
Vol 113 (9) ◽  
pp. 2366-2369 ◽  
Author(s):  
Xilian Jin ◽  
Xiao-Jia Chen ◽  
Tian Cui ◽  
Ho-kwang Mao ◽  
Huadi Zhang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
Fermi Surface ◽  
Density Functional ◽  
Alkali Metals ◽  
Alkaline Earth ◽  
Density Functional Theory Calculations ◽  
Alkaline Earth Metals ◽  
Functional Theory ◽  
Surface Filling

At room environment, all materials can be classified as insulators or metals or in-between semiconductors, by judging whether they are capable of conducting the flow of electrons. One can expect an insulator to convert into a metal and to remain in this state upon further compression, i.e., pressure-induced metallization. Some exceptions were reported recently in elementary metals such as all of the alkali metals and heavy alkaline earth metals (Ca, Sr, and Ba). Here we show that a compound of CLi4 becomes progressively less conductive and eventually insulating upon compression based on ab initio density-functional theory calculations. An unusual path with pressure is found for the phase transition from metal to semimetal, to semiconductor, and eventually to insulator. The Fermi surface filling parameter is used to describe such an antimetallization process.

scholarly journals Robust and efficient calculation of activation energy by automated path search and density functional theory

2021 ◽  
Vol 5 (3) ◽  
Author(s):  
Koki Ueno ◽  
Kazuhide Ichikawa ◽  
Kosei Sato ◽  
Daisuke Sugita ◽  
Satoshi Yotsuhashi ◽  
...  
Keyword(s):  
Activation Energy ◽  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Efficient Calculation ◽  
Path Search

DENSITY FUNCTIONAL THEORY STUDY OF H2O ADSORPTION AND DISSOCIATION ON Al (111) SURFACE

2013 ◽  
Vol 12 (05) ◽  
pp. 1350035 ◽  
Author(s):  
LIXIA YANG ◽  
XIAOLI LEI ◽  
JUN FENG ◽  
YUXIN ZHANG ◽  
MINGXING LIU
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Catalytic Effect ◽  
Geometry Optimization ◽  
Vacancy Defect ◽  
Hydroxyl Group ◽  
Dissociation Pathway ◽  
Functional Theory ◽  
Lower Activation ◽  
Adsorption And Dissociation

Comparative study about the adsorption and dissociation behaviors of H2O molecule on clean and vacancy defective Al (111) surface was conducted by extensive density functional theory (DFT) calculations, the interaction mechanisms between H2O molecule and Al (111) surface were also figured out. Geometry optimization results indicated that H2O molecule was apt to be adsorbed at top site on these two kinds of surfaces, whereas, the adsorption configurations, the adsorption type and inclination of H2O molecule planes away from the normal were different. The calculated adsorption energies demonstrated that the adsorption of H2O molecule occurred more readily on vacancy defective Al (111) surface. The electron density distribution indicated that the vacancy defect enhanced the interactions between H2O molecule and surface Al atoms. Further analysis of the density of states (DOS) showed that the vacancy defect increased the number of bonding electrons between H2O molecule and surface Al atoms. The detailed exploration of dissociation pathways demonstrated that the dissociation of H2O molecule on these two kinds of surfaces was a two-step process: (1) H2O → H + OH , (2) OH → H + O . However, for each step the dissociation pathway variations on vacancy defective Al (111) surface were different with those on clean Al (111) surface. Compared with the first step, the dissociation of hydroxyl group into O atom and H atom was kinetically difficult. The calculated lower activation energy barriers on vacancy defective Al (111) surface showed that the vacancy defect had catalytic effect for the dissociation of H2O molecule to some extent, especially for the first step.

DFT studies of complexes between ethylenediamine tetraacetate and alkali and alkaline earth cations

2009 ◽  
Vol 87 (10) ◽  
pp. 1492-1498 ◽  
Author(s):  
Melissa Gajewski ◽  
Mariusz Klobukowski
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Alkaline Earth ◽  
Dft Studies ◽  
Functional Theory ◽  
Alkaline Earth Cations ◽  
Ethylenediamine Tetraacetate

Density functional theory (DFT) calculations for M–(C10H12N2O84–) and M–(H2O)6, where M = Na+, K+, Rb+, Mg2+, Ca2+, and Sr2+, and (C10H12N2O84–) = EDTA4–, were carried out at both all-electron and pseudopotential levels. Results from these four methods were compared, and it was found that the ions bind to EDTA4– with selectivity of Mg2+ > Ca2+ > Sr2+ > Na+ > K+ > Rb+.

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