First principles calculations on oxygen vacant hydrated α-MnO2 for activating water oxidation and its self-healing mechanism

2016 ◽  
Vol 18 (32) ◽  
pp. 22196-22202 ◽  
Author(s):  
Kruthika Ganesan ◽  
P. Murugan
Keyword(s):  
Oxygen Vacancy ◽  
Water Molecule ◽  
First Principles ◽  
Water Oxidation ◽  
Proton Transport ◽  
Water Molecules ◽  
Self Healing ◽  
First Principles Calculations

In the presence of an oxygen vacancy, two water molecules in the tunnel of an α-MnO2 lattice form a dimer and dissociate into ions, which can activate water oxidation. And also self-healing can happen if at least one more water molecule is available in the tunnel for proton transport.

First-principles calculations of oxygen vacancy in CaO crystal

2020 ◽  
Vol 74 (10) ◽  
Author(s):  
Kaili Wu ◽  
Tingyu Liu ◽  
Ruxi Sun ◽  
Jiamei Song ◽  
Chunyu Shi
Keyword(s):  
Oxygen Vacancy ◽  
First Principles ◽  
First Principles Calculations

First-Principles Study on Co-Doped ZnO with Oxygen Vacancy

2010 ◽  
Vol 154-155 ◽  
pp. 124-129
Author(s):  
Zhen Zhen Weng ◽  
Zhi Gao Huang ◽  
Wen Xiong Lin
Keyword(s):  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Exchange Interactions ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Ferromagnetic Exchange ◽  
Ferromagnetic Ground State ◽  
Doped Zno ◽  
Co Doped

The interatomic exchange interactions and the electronic structure of Co-doped ZnO with and without oxygen vacancy have been investigated by the first-principles calculations based on density functional theory. It is found that the oxygen vacancy can strengthen the ferromagnetic exchange interaction between Co atoms and might be available for carrier mediation. The oxygen vacancy near to the Co atoms is more favorable for the ferromagnetic ground state.

Dissociation of H2O molecule adsorbed on Si (001) 2×1 surface: a theoretical study

2008 ◽  
Vol 1145 ◽  
Author(s):  
Hyun-Chul Oh ◽  
Hwa-Il Seo ◽  
Yeong-Cheol Kim
Keyword(s):  
Water Molecule ◽  
Room Temperature ◽  
Surface Coverage ◽  
Theoretical Study ◽  
Surface Model ◽  
Water Molecules ◽  
First Principles Calculations ◽  
Adsorption Sites ◽  
Adsorption Surface ◽  
Adsorption And Dissociation

AbstractThe adsorption and dissociation behavior of water molecule below and above the critical dissociation temperatures were studied by first principles calculations. We found that water-molecule adsorption (surface coverage, θ=0.25) on the down Si atom of a Si dimer in two dimers surface model was 0.26 eV more favorable than that on the up Si atom. The activation energies of water molecule on the down Si atom for interdimer and intradimer dissociations were 0.17 eV and 0.20 eV, respectively. Due to the lower activation energy, the water molecule splits into H and OH immediately once it adsorbs on down Si atom of the Si (001) surface at room temperature. There were three different adsorption sites among four sites of the two dimers for the second water molecule (θ=0.5): one was preoccupied by OH of the first water molecule; up Si atom of the same-dimer with 76.3 % probability, up Si atom of the adjacent-dimer with 23.6 % probability, and down Si atom of the adjacent-dimer with 0.1 % probability. Thus, ½ monolayer of OH sites on the Si (001) surface are irregularly distributed when water molecules are adsorbed and dissociated at room temperature.

scholarly journals Engineering Graphene Oxide/Water Interface from First Principles to Experiments for Electrostatic Protective Composites

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1596
Author(s):  
Luca Valentini ◽  
Silvia Bittolo Bon ◽  
Giacomo Giorgi
Keyword(s):  
Graphene Oxide ◽  
First Principles ◽  
Composite Fiber ◽  
Water Molecules ◽  
Liquid Droplets ◽  
First Principles Calculations ◽  
Voltage Output ◽  
Global Spread ◽  
Protective Fabrics ◽  
Airborne Viruses

From the global spread of COVID-19 we learned that SARS-CoV-2 virus can be transmitted via respiratory liquid droplets. In this study, we performed first-principles calculations suggesting that water molecules once in contact with the graphene oxide (GO) layer interact with its functional groups, therefore, developing an electric field induced by the heterostructure formation. Experiments on GO polymer composite film supports the theoretical findings, showing that the interaction with water aerosol generates a voltage output signal of up to −2 V. We then developed an electrostatic composite fiber by the coagulation method mixing GO with poly(methyl methacrylate) (PMMA). These findings could be used to design protective fabrics with antiviral activity against negatively charged spike proteins of airborne viruses.

A Promising New Photo-Catalyst InVO4 for Water Molecule Decomposition in the Visible Wavelength Region

2002 ◽  
Vol 730 ◽  
Author(s):  
M. Oshikiri ◽  
A. P. Seitsonen ◽  
M. Parrinello ◽  
M. Boero ◽  
J. Ye ◽  
...  
Keyword(s):  
Water Molecule ◽  
First Principles ◽  
Wavelength Region ◽  
Exposed Surface ◽  
First Principles Calculations ◽  
Crucial Step ◽  
Photo Catalyst ◽  
Photo Catalytic Activity ◽  
Visible Light Range ◽  
Decomposition Of Water

AbstractA promising vanadium-based photo-catalyst (InVO4) has been proposed recently by our group. This catalyst has been shown to be active in the visible light range, up to a wavelength of about 600 nm, and is able to promote the decomposition of water. In this paper, we focus on its electronic structure, computed via first principles calculations, in order to figure out analogies and differences with similar systems (InNbO4, InTaO4 and BiVO4) that have already been reported to act as photo-catalysts. An attempt is made to address the problem of the wavelength dependency of the photo catalytic activity of the InMO4 (M = V, Nb, Ta) family and how this is related to the crystal structure. Finally, by using an ab initio molecular dynamics approach, we inspect the relaxation/reconstruction phenomena occurring at the exposed surface of the InVO4 catalyst induced by the absorption of a water molecule, that represents a crucial step in the catalysis reaction.

Vibrational states of nano-confined water molecules in beryl investigated by first-principles calculations and optical experiments

2017 ◽  
Vol 19 (45) ◽  
pp. 30740-30748 ◽  
Author(s):  
M. A. Belyanchikov ◽  
E. S. Zhukova ◽  
S. Tretiak ◽  
A. Zhugayevych ◽  
M. Dressel ◽  
...  
Keyword(s):  
Optical Spectroscopy ◽  
First Principles ◽  
Comprehensive Analysis ◽  
Water Molecules ◽  
First Principles Calculations ◽  
Confined Water ◽  
Vibrational States

Using the DFT approach and optical spectroscopy, we provide a comprehensive analysis of IR excitation of water molecules confined in beryl nanopores.

First-principles study on the geometry and electronic structures of IIIA atoms doped α-Al2O3:VO

2014 ◽  
Vol 92 (10) ◽  
pp. 1135-1140 ◽  
Author(s):  
L. Ao ◽  
J.L. Nie ◽  
X. Xiang ◽  
X.T. Zu ◽  
J. Huang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Oxygen Vacancy ◽  
Electronic Property ◽  
First Principles ◽  
Electronic Structures ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Hexagonal Symmetry ◽  
Α Al2o3 ◽  
Metal Doped

We investigate the geometry and electronic structures of α-Al2O3:VO + AlX systems based on first-principles calculations where VO represents one oxygen vacancy and AlX stands for IIIA atoms (B, Ga, In, and Tl) substituting of one Al atom. It is found that all the aluminates maintain the hexagonal symmetry as the pure α-Al2O3 structure and the lattice parameters a, b, and c are expanded with the increase of the IIIA atoms radius. The electronic property analysis indicates that the band gaps are considerably reduced and the reductions are also related to the radius of doping atoms. But unlike the situation of transition metal doped α-Al2O3 the decreases of the band gap are not due to the spreading of d states, but are mainly owing to the ns states at the bottom of the conduction band.

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