Adsorption and splitting of H2S on 2D-ZnO1−xNy: first-principles analysis

2014 ◽  
Vol 16 (22) ◽  
pp. 10719-10726 ◽  
Author(s):  
Summayya Kouser ◽  
Umesh V. Waghmare ◽  
Nacir Tit
Keyword(s):  
First Principles ◽  
Oxygen Vacancies ◽  
First Principles Calculations ◽  
Novel Applications ◽  
Green Fuel

Based on first-principles calculations, we report novel applications of an inorganic analogue of graphene (2D-ZnO) in the detection and capture of toxic H2S gas, its dissociation and conversion to a green fuel, hydrogen, highlighting the role of N-substitution and oxygen vacancies.

Evaluation of the role of oxygen vacancies in La3GaGe5O16:Tb3+ persistent phosphor

2017 ◽  
Vol 31 (13) ◽  
pp. 1750144 ◽  
Author(s):  
He Duan ◽  
Ze Jia Lin ◽  
You Zhong Dong ◽  
Yan Huang
Keyword(s):  
First Principles ◽  
Oxygen Vacancies ◽  
Oxygen Deficiency ◽  
Ring Structure ◽  
Persistent Luminescence ◽  
First Principles Calculations ◽  
Color Tunable ◽  
Luminescence Performance ◽  
Trap Levels

The persistent luminescence performance of a novel color-tunable Tb[Formula: see text]-doped La[Formula: see text]GaGe[Formula: see text]O[Formula: see text] phosphor has been modified by oxygen-deficiency control with an aim to explore the strategy to improve the persistent luminescence property. First-principles calculations were combined with thermoluminescence (TL) measurements to evaluate the role of oxygen vacancies in persistent luminescence of La[Formula: see text]GaGe[Formula: see text]O[Formula: see text]:Tb[Formula: see text] persistent phosphor. Our results show that the oxygen vacancies that act as an electron trap center have a limited contribution to the persistent luminescence. The formation of the ring structure of La[Formula: see text]GaGe[Formula: see text]O[Formula: see text] crystal and the resulting localized trap levels are very different from that of other outstanding persistent phosphors, like Sr[Formula: see text]MgSi[Formula: see text]O[Formula: see text], etc. Such differences are closely related to the inferior performance of La[Formula: see text]GaGe[Formula: see text]O[Formula: see text]:Tb[Formula: see text] persistent phosphor.

scholarly journals A DFT investigation of the role of oxygen vacancies on the structural, electronic and magnetic properties of ATiO3 (A = Mn, Fe, Ni) multiferroic materials

2018 ◽  
Vol 20 (45) ◽  
pp. 28382-28392 ◽  
Author(s):  
R. A. P. Ribeiro ◽  
E. Longo ◽  
J. Andrés ◽  
S. R. de Lazaro
Keyword(s):  
Magnetic Properties ◽  
First Principles ◽  
Oxygen Vacancies ◽  
First Principles Calculations ◽  
Deep Insight ◽  
Multiferroic Materials ◽  
Multiferroic Properties ◽  
Surface Models ◽  
Insight Into

In order to achieve deep insight into the multiferroic behavior and electronic properties of intrinsic oxygen vacancies in ATiO3 (A = Mn, Fe, Ni), first-principles calculations were carried out for bulk and non-polar (110) surface models, showing that controlling oxygen vacancies can be a valuable strategy to tailor the multiferroic properties.

An effective and efficient approach to p-type AlN by Be2:O codoping from first-principles calculations

2016 ◽  
Vol 30 (20) ◽  
pp. 1650257
Author(s):  
Meng Zhao ◽  
Wenjun Wang ◽  
Jun Wang ◽  
Junwei Yang ◽  
Weijie Hu ◽  
...  
Keyword(s):  
First Principles ◽  
Ionization Energy ◽  
Hole Concentration ◽  
Valence Band Maximum ◽  
First Principles Calculations ◽  
Mutual Compensation ◽  
Efficient Approach ◽  
P Type ◽  
Codoping Method

Various Be:O-codoped AlN crystals have been investigated via first-principles calculations to evaluate the role of the different combinations in effectively and efficiently inducing p-type carriers. It is found that the O atom is favored to bond with two Be atoms. The formed Be2:O complexes decrease the acceptor ionization energy to 0.11 eV, which is 0.16 eV lower than that of an isolated Be in AlN, implying that the hole concentration could probably be increased by 2–3 orders of magnitude. The electronic structure of Be2:O-codoped AlN shows that the lower ionization energy can be attributed to the interaction between Be and O. The Be–O complexes, despite failing to induce p-type carriers for the mutual compensation of Be and O, introduce new occupied states on the valence-band maximum (VBM) and hence the energy needed for the transition of electrons to the acceptor level is reduced. Thus, the Be2:O codoping method is expected to be an effective and efficient approach to realizing p-type AlN.

Computational and Experimental Insights into the Role of Acidic Molecules on the Corrosion Behavior on 7A46 Aluminum Alloy

2021 ◽  
Vol 21 (4) ◽  
pp. 2221-2233
Author(s):  
Yaru Liu ◽  
Qinglin Pan ◽  
Xiangdong Wang ◽  
Ye Ji ◽  
Qicheng Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
First Principles ◽  
First Principles Calculations ◽  
Corrosive Media ◽  
Corrosion Depth ◽  
Corrosion Mechanisms ◽  
Nanoscale Level

The corrosion mechanisms for different corrosive media on the aged 7A46 aluminum alloy were systematically investigated at nanoscale level. The combination of empirical intergranular and exfoliation corrosion behavior was employed, and coupled with first-principles calculations. Results revealed that the dispersed distribution of matrix precipitates (MPs) leads to the enhancement of the corrosion resistance pre-ageing (PA) followed by double-ageing (PA-DA) alloy. The deepest corrosion depth of PA-DA alloy was in hydrochloric acid, and the calculation result demonstrates that the passivation effect in combination with the accumulation of corrosion products in nitric acid protect the PA-DA alloy from further corrosion.

scholarly journals First principles calculations of optical properties for oxygen vacancies in binary metal oxides

2019 ◽  
Vol 150 (4) ◽  
pp. 044702 ◽  
Author(s):  
Jack Strand ◽  
Sergey K. Chulkov ◽  
Matthew B. Watkins ◽  
Alexander L. Shluger
Keyword(s):  
Optical Properties ◽  
Metal Oxides ◽  
First Principles ◽  
Oxygen Vacancies ◽  
First Principles Calculations ◽  
Binary Metal ◽  
Binary Metal Oxides

Local condensation around oxygen vacancies in t-LaNbO4 from first principles calculations

2009 ◽  
Vol 11 (27) ◽  
pp. 5550 ◽  
Author(s):  
Akihide Kuwabara ◽  
Reidar Haugsrud ◽  
Svein Stølen ◽  
Truls Norby
Keyword(s):  
First Principles ◽  
Oxygen Vacancies ◽  
First Principles Calculations

The Role of Phase Stability in Ductile, Ordered B2 Intermetallics

2006 ◽  
Vol 980 ◽  
Author(s):  
James R. Morris ◽  
Yiying Ye ◽  
Maja Krcmar ◽  
Chong Long Fu
Keyword(s):  
Phase Stability ◽  
First Principles ◽  
Tensile Ductility ◽  
Stacking Faults ◽  
Low Energy ◽  
First Principles Calculations ◽  
Phase Competition ◽  
Transformation Pathway ◽  
Shape Memory Materials

AbstractWe discuss the underlying atomistic mechanism for experimentally observed large tensile ductility in various strongly ordered B2 intermetallic compounds. First-principles calculations demonstrate that all of the compounds exhibit little energy differences between the B2, B27 and B33 phases. These calculations relate observations of ductility in YAg, YCu and ZrCo to shape-memory materials including NiTi. One transformation pathway between the B2 and B33 phases establishes a connection between this phase competition, and stacking faults on the {011}B2 plane. The low energy of such a stacking fault will lead to splitting of the b=<100> dislocations into b/2 partials, observed in ZrCo, TiCo, and in the B19' phase of NiTi. Calculations demonstrate that this pathway is competitive with the traditional pathway for NiTi.

Electronic Structure and Hydrogen Desorption in NaAlH4

2004 ◽  
Vol 837 ◽  
Author(s):  
S. Li ◽  
P. Jena ◽  
C. M. Araujo ◽  
R. Ahuja
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Metal Hydrides ◽  
Hydrogen Desorption ◽  
Light Metal ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Design And Synthesis

ABSTRACTFirst principles calculations based on gradient corrected density functional theory are carried out to understand the electronic structure and mechanisms responsible for desorption of hydrogen from Ti doped and vacancy containing sodium-alanate (NaAlH4). The energy necessary to remove a hydrogen atom from Ti doped NaAlH4 is significantly smaller than that from pristine NaAlH4 irrespective of whether Ti substitutes the Na or the Al site. However, the presence of Na and Al vacancies is shown to play an even more important role: The removal of hydrogen associated with both Na and Al vacancies is found to be exothermic. It is suggested that this role of vacancies can be exploited in the design and synthesis of complex light metal hydrides suitable for hydrogen storage.

Theoretical search for high-performance thermoelectric donor–acceptor copolymers: the role of super-exchange couplings

2020 ◽  
Vol 8 (41) ◽  
pp. 21852-21861
Author(s):  
Xue Yong ◽  
Gang Wu ◽  
Wen Shi ◽  
Zicong Marvin Wong ◽  
Tianqi Deng ◽  
...  
Keyword(s):  
Effective Mass ◽  
Power Factor ◽  
First Principles ◽  
High Performance ◽  
First Principles Calculations ◽  
Thermoelectric Power Factor ◽  
Hole Effective Mass ◽  
Donor Acceptor ◽  
Weak Electron

First-principles calculations of a series of representing D–A copolymers demonstrated the strong Super-Exchange couplings induce not only small hole effective mass but also weak electron-phonon couplings, and eventually high thermoelectric power factor.

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