Hydrogen storage in Beryllium decorated graphene with double vacancy and porphyrin defect — A first principles study

2017 ◽  
Vol 10 (03) ◽  
pp. 1750023 ◽  
Author(s):  
M. Mahendran ◽  
B. Rekha ◽  
S. Seenithurai ◽  
R. Kodi Pandyan ◽  
S. Vinodh Kumar
Keyword(s):  
Hydrogen Storage ◽  
Bond Length ◽  
Density Functional ◽  
Vacancy Defect ◽  
Ambient Conditions ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Average Binding Energy ◽  
Defective Sites

Beryllium (Be)-decorated graphene with 585 double carbon vacancy defect and nitrogen-doped porphyrin defect are investigated for hydrogen storage applications using the first principle calculation based on density functional theory. It is found that the Be atom disperses well in the defective sites of graphene and prevents clustering. For the case of Be-decorated 585 double vacancy graphene, only two H2 molecules are adsorbed via Kubas interaction with the stretched H–H bond length of 0.8 Å. In Be-decorated porphyrin defect graphene system, four H2 molecules are molecularly chemisorbed with the H–H bond length of 0.77 Å. The chemisorptions are due to the hybridization between Be-p orbital and the H-[Formula: see text] orbital. The average binding energy of H2 molecule is found to be 0.43[Formula: see text]eV/H2 which lies within the required range that can permit recycling of H2 molecules under ambient conditions.

scholarly journals First Principle Study on Atomic Scale Structures of Cathode in Aluminium-ion Battery Using Various van der Waals Corrections

2020 ◽  
Vol 213 ◽  
pp. 01023
Author(s):  
Kaihao Geng ◽  
Haining Cao ◽  
Meng-Chang Lin
Keyword(s):  
Density Functional ◽  
Van Der Waals ◽  
Structural Features ◽  
Atomic Scale ◽  
First Principle ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Aluminium Ion ◽  
Scale Structures

There is still controversy on the atomistic configuration of aluminium-ion batteries (AIB) cathode when using first principle calculation based on density functional theory (DFT). We examined the relevant cathodic structures of Al/graphite battery by employing several van der Waals (vdW) corrections. Among them, DFT-TS method was determined to be a better dispersion correction in correctly rendering structural features already found through experiment investigations. The systematic comparison paved the way to the choice of vdW parameters in first principle calculation of graphitic electrode.

scholarly journals A First-Principles Study on Titanium-Decorated Adsorbent for Hydrogen Storage

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6845
Author(s):  
Kai Ma ◽  
Erfei Lv ◽  
Di Zheng ◽  
Weichun Cui ◽  
Shuai Dong ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculation ◽  
Partial Density ◽  
Ambient Conditions ◽  
Functional Theory ◽  
Hydrogen Molecules ◽  
Theory Calculation ◽  
Hydrogen Storage Medium

Based on density functional theory calculation, we screened suitable Ti-decorated carbon-based hydrogen adsorbent structures. The adsorption characteristics and adsorption mechanism of hydrogen molecules on the adsorbent were also discussed. The results indicated that Ti-decorated double vacancy (2 × 2) graphene cells seem to be an efficient material for hydrogen storage. Ti atoms are stably embedded on the double vacancy sites above and below the graphene plane, with binding energy higher than the cohesive energy of Ti. For both sides of Ti-decorated double vacancy graphene, up to six H2 molecules can be adsorbed around each Ti atom when the adsorption energy per molecule is −0.25 eV/H2, and the gravimetric hydrogen storage capacity is 6.67 wt.%. Partial density of states (PDOS) analysis showed that orbital hybridization occurs between the d orbital of the adsorbed Ti atom and p orbital of C atom in the graphene layer, while the bonding process is not obvious during hydrogen adsorption. We expect that Ti-decorated double vacancy graphene can be considered as a potential hydrogen storage medium under ambient conditions.

Electronic Structure of Wurtzite Ga0.75Al0.25N: A First Principle Calculation

2014 ◽  
Vol 556-562 ◽  
pp. 43-46
Author(s):  
Ming Zhu Yang ◽  
Mei Shan Wang
Keyword(s):  
Density Functional ◽  
First Principle ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Solar Blind ◽  
Direct Band ◽  
Total Energies ◽  
Pseudo Potential ◽  
Theoretical Foundations

In order to lay theoretical foundations for preparation of Ga0.75Al0.25N photocathodes, research on ternary Ш-V alloys Ga0.75Al0.25N are carried on. Using CASTEP software package based on density functional theory within a plane wave ultrasoft pseudo potential scheme, total energies, band structures, density of states, and charge distribution of three different structures of wurtzite Ga0.75Al0.25N are calculated. Results show that the structure in which Al atoms in para-positon of interlayer is most stable. Ga0.75Al0.25N is semiconductor with direct band gap. The threshold wavelength is 321.8nm which can satisfy the need of preparation of “solar blind” photocathodes.

Enhanced ferromagnetic properties of Cu doped two-dimensional GaN monolayer

2015 ◽  
Vol 26 (01) ◽  
pp. 1550009 ◽  
Author(s):  
Fayyaz Hussain ◽  
Y. Q. Cai ◽  
M. Junaid Iqbal Khan ◽  
Muhammad Imran ◽  
Muhammad Rashid ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Density Functional ◽  
Magnetic Coupling ◽  
First Principle ◽  
Two Dimensional ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Cu Dopant

We demonstrate enhanced ferromagnetism in copper doped two-dimensional GaN monolayer ( GaN -ML). Our first principle calculation based on density functional theory predicted that nonmagnetic Cu -dopant with concentration of 6.25% to be ferromagnetic (FM) in 2D GaN layer which carries a magnetic moment of 2.0 μB per Cu atom and it is found to be long range magnetic coupling among the Cu -dopant. The Cu-dopant in 2D GaN -ML which can be explained in terms of p-d hybridization at Curie temperature and this dopant prefer the FM behavior in 2D GaN layer. Hence Cu doped 2D GaN layer shows strong magnetic properties so that it is a promising material in the field of spintronics.

Half-metallic ferromagnetism in hypothetical wurtzite structure chromium chalcogenides

2004 ◽  
Vol 19 (9) ◽  
pp. 2738-2741 ◽  
Author(s):  
Ming Zhang ◽  
Ekkes Brück ◽  
Frank R. de Boer ◽  
Guodong Liu ◽  
Haining Hu ◽  
...  
Keyword(s):  
Density Functional ◽  
Wurtzite Structure ◽  
First Principle ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

The hypothetical wurtzite structure chromium chalcogenides were investigated through first-principle calculation within density-functional theory. All compounds are predicted to be true half-metallic ferromagnets with an integer Bohr magneton of 4 μB per unit. Their half-metallic gaps are 1.147, 0.885, and 0.247 eV at their equilibrium volumes for wurtzite-type CrM (M = S, Se, and Te), respectively. The half-metallicity can be maintained even when volumes are expanded by more than 20% for all compounds and compressed by more than 20%, 20%, and 5%, for CrS, CrSe, and CrTe, respectively.

scholarly journals Surface Properties and Floatability Comparison of Aegirite and Specularite by Density Functional Theory Study and Experiment

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 782 ◽  
Author(s):  
Mingyang Li ◽  
Jun Liu ◽  
Xiangpeng Gao ◽  
Yiming Hu ◽  
Xiong Tong ◽  
...  
Keyword(s):  
Surface Properties ◽  
Density Functional ◽  
Surface Relaxation ◽  
First Principle ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Potential Measurement ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Bond Population

Understanding the differences in surface properties between aegirite and specularite is of great significance to study their separation. In this work, the surface properties of aegirite and specularite, as well as their relationships to floatability, have been explored by first principle calculation, flotation, and Zeta potential measurement. The surface relaxation indicated that the specularite (001) surface appeared to show more surface reconstruction. The unsatisfied bond properties, Mulliken bond population, and surface charge showed that the floatability of specularite was superior to that of aegirite. The flotation results showed that the hydrophobicity of specularite was higher than that of aegirite with dodecylamine (DDA) as the collector. It is infeasible to separate specularite from aegirite by flotation using starch as the depressant, and research of effective reagents with high affinity to the element Si is the subclinical breakthrough point of specularite/aegirite separation.

scholarly journals Modelling carbyne C12-ring calcium decorated for hydrogen storage

2018 ◽  
Vol 64 (6) ◽  
pp. 634 ◽  
Author(s):  
Luis Alberto Desales Guzmán ◽  
Juan Horacio Pacheco Sánchez ◽  
Frank Jhonatan Isidro Ortega ◽  
Genoveva García Rosales
Keyword(s):  
Hydrogen Storage ◽  
Density Functional ◽  
Population Analysis ◽  
Generalized Gradient ◽  
Mulliken Population ◽  
Functional Theory ◽  
Weight Percentage ◽  
Average Binding Energy ◽  
Total Energies ◽  
Materials Studio

We computationally investigate the hydrogen storage properties of C12 carbyne structure decorated with one and up to six calcium (Ca) atoms adsorbed to outer surface. The calculations are carried out by density functional theory DFT with the generalized gradient approximation PW91 (Perdew and Wang) as implemented in the modeling and simulation Materials Studio software. Dmol3 is used to calculate, total energies, charge density HOMO-LUMO and Mulliken population analysis. Based on these results, up to six H2 molecules per Ca atom can be physisorbed with an average binding energy of 0.1272 eV per H2 molecule. The study is extended to a system with six calcium atoms, which can adsorb up to 36 H2 molecules. This leads to 15.87 weight percentage (wt %) for the gravimetric hydrogen storage capacity. According to these results, the calcium-coated carbyne C12 structure is a good candidate for hydrogen storage with application to fuel cells.

Enhanced Photoelectrocatalytic performance of α-MnO2 by Sb and N charge compensation  

2021 ◽  
Author(s):  
Min-Min Guo ◽  
Huimin Yang ◽  
Yuting Du ◽  
Yingjin Wang ◽  
Xiaojing Yang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Performance Test ◽  
Charge Compensation ◽  
Active Area ◽  
First Principle ◽  
Photoelectrochemical Performance ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation

The photoelectrocatalytic performance of (Sb,N)-MnO2 are explored by experiment and first principle calculation based on density functional theory. The photoelectrochemical performance test shows that 6% (Sb,N)-MnO2 with maximum electrochemical active area...

scholarly journals Studying on the Addition Reaction Mechanism of Ethylene and Butadiene Based on Density Functional Theory

2021 ◽  
Author(s):  
Kangning Li ◽  
Wei-lin Ma ◽  
Wen-li Xie
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Addition Reaction ◽  
Exothermic Reaction ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Calculated Activation Energy ◽  
Calculated Activation

Abstract According to the first principle calculation, the addition reaction mechanism of ethylene and butadiene is determined. The reactant, transition state (TS) and product of this addition reaction are confirmed by optimization calculation and frequency analysis. To verify the correctness of the reaction process, we also calculated the reaction path. Result demonstrates that the addition reaction of ethylene and butadiene is an exothermic reaction. Charge transfer is used to explain this novel reaction. The activation energy of the addition reaction of ethylene and butadiene is 0.83 eV, and the heat release of the whole reaction is 2.01 eV. The molecular structure, charge distribution and energy of butadiene and ethylene are investigated at the molecular level. The calculated activation energy is helpful for understanding the cyclic addition reaction of butadiene and ethylene, providing theoretical guidance for experiments and deepening people's understanding of this reaction.

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