Enhancing nitrobenzene reduction to azoxybenzene by regulating the O-vacancy defects over rationally tailored CeO2 nanocrystals

2021 ◽  
pp. 151343
Author(s):  
Xueke Zhou ◽  
Yang Yang ◽  
Jiaben Wang ◽  
Renwei Jia ◽  
Shaojun Liu ◽  
...  
Keyword(s):  
Vacancy Defects ◽  
Nitrobenzene Reduction ◽  
O Vacancy

Effect of O-vacancy defects on the Schottky barrier heights in Ni/SiO2 and Ni/HfO2 interfaces

2012 ◽  
Vol 407 (15) ◽  
pp. 2907-2910 ◽  
Author(s):  
Hyeon-Kyun Noh ◽  
Young Jun Oh ◽  
K.J. Chang
Keyword(s):  
Schottky Barrier ◽  
Vacancy Defects ◽  
Barrier Heights ◽  
O Vacancy

scholarly journals The role of intrinsic vacancy defects in the electronic and magnetic properties of Sr3SnO: a first-principles study

RSC Advances ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 6880-6888 ◽  
Author(s):  
Javaria Batool ◽  
Syed Muhammad Alay-e-Abbas ◽  
Adnan Ali ◽  
Khalid Mahmood ◽  
Shaheen Akhtar ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Stability Diagram ◽  
Vacancy Defects ◽  
Electronic And Magnetic Properties ◽  
O Vacancy ◽  
Formation Energies ◽  
Thermodynamic Stability Diagram

The thermodynamic stability diagram and formation energies of intrinsic vacancy defects in Sr3SnO. Sr and O vacancy containing Sr3SnO is non-magnetic, while ferromagnetism is achieved in Sn deficient Sr3SnO.

Electronic Structure of O-vacancy in High-k Dielectrics and Oxide Semiconductors

2011 ◽  
Vol 1370 ◽  
Author(s):  
Kee Joo Chang ◽  
Byungki Ryu ◽  
Hyeon-Kyun Noh ◽  
Junhyeok Bang ◽  
Eun-Ae Choi
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Device Performance ◽  
Oxide Semiconductors ◽  
Vacancy Defects ◽  
High K ◽  
Quasiparticle Energy ◽  
O Vacancy ◽  
Hybrid Density Functional

ABSTRACTFirst-principles density functional calculations are performed to investigate the electronic properties of O-vacancy defects in high-k HfO2, Si/HfO2 interface, and amorphous oxide semiconductors. The role of O-vacancy in device performance is discussed by comparing the results of the GGA, hybrid density functional, and quasiparticle energy calculations.

scholarly journals The effect of native vacancy defects on electronic and magnetic properties of ZnO:Mn system

2020 ◽  
Vol 34 (21) ◽  
pp. 20502100
Author(s):  
Chun-An Wang ◽  
Jun-Xian Li ◽  
Si-Lie Fu ◽  
Jia-Yi Bao ◽  
Tao Lei ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Nearest Neighbor ◽  
Antiferromagnetic Phase ◽  
Vacancy Defects ◽  
Electronic And Magnetic Properties ◽  
Doped Zno ◽  
O Vacancy ◽  
P Type ◽  
Mn Doped ◽  
Zn Vacancy

In this paper, the plane wave ultra-soft pseudopotential method was performed to analyze the effect of neutral Zn vacancy (V[Formula: see text]) and O vacancy (V[Formula: see text]) on the electronic and magnetic properties of Mn-doped ZnO systems. In a [Formula: see text] ZnO:Mn supercell, the sites of V[Formula: see text] and V[Formula: see text] were set as nearest neighbor, next nearest neighbor and far nearest neighbor relative to Mn site, respectively. The results indicated that V[Formula: see text] is easier to be produced than V[Formula: see text] in the ZnO:Mn system, and both kinds of defects are more likely to be generated in the nearest neighbor of Mn site. Meanwhile, the ZnO:Mn-V[Formula: see text] system is p-type conductive. The farther the distance between V[Formula: see text] and Mn, the better the conductivity of the system. Contrary to V[Formula: see text], the ZnO:Mn-V[Formula: see text] system is n-type conductive. The farther the distance between V[Formula: see text] and Mn, the worse the conductivity of the system. Furthermore, the ZnO:Mn systems containing neutral V[Formula: see text] or V[Formula: see text] are both likely to be in antiferromagnetic phase. However, the presence of V[Formula: see text] will enhance the possibility, while V[Formula: see text] will weaken it.

Spectroscopic studies of O-vacancy defects in transition metal oxides

2007 ◽  
Vol 18 (S1) ◽  
pp. 263-266 ◽  
Author(s):  
G. Lucovsky ◽  
J. Lüning ◽  
L. B. Fleming ◽  
M. D. Ulrich ◽  
J. E. Rowe ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Spectroscopic Studies ◽  
Vacancy Defects ◽  
O Vacancy

scholarly journals Millisecond lattice gasification for high-density CO2- and O2-sieving nanopores in single-layer graphene

2021 ◽  
Vol 7 (9) ◽  
pp. eabf0116
Author(s):  
Shiqi Huang ◽  
Shaoxian Li ◽  
Luis Francisco Villalobos ◽  
Mostapha Dakhchoune ◽  
Marina Micari ◽  
...  
Keyword(s):  
Single Layer ◽  
High Density ◽  
Single Layer Graphene ◽  
Pore Density ◽  
Vacancy Defects ◽  
Carbon Gasification ◽  
Layer Graphene ◽  
Gas Molecules ◽  
Good Agreement

Etching single-layer graphene to incorporate a high pore density with sub-angstrom precision in molecular differentiation is critical to realize the promising high-flux separation of similar-sized gas molecules, e.g., CO2 from N2. However, rapid etching kinetics needed to achieve the high pore density is challenging to control for such precision. Here, we report a millisecond carbon gasification chemistry incorporating high density (>1012 cm−2) of functional oxygen clusters that then evolve in CO2-sieving vacancy defects under controlled and predictable gasification conditions. A statistical distribution of nanopore lattice isomers is observed, in good agreement with the theoretical solution to the isomer cataloging problem. The gasification technique is scalable, and a centimeter-scale membrane is demonstrated. Last, molecular cutoff could be adjusted by 0.1 Å by in situ expansion of the vacancy defects in an O2 atmosphere. Large CO2 and O2 permeances (>10,000 and 1000 GPU, respectively) are demonstrated accompanying attractive CO2/N2 and O2/N2 selectivities.

scholarly journals Barium Titanium Oxynitride from Ammonia-Free Nitridation of Reduced BaTiO3

Inorganics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 62
Author(s):  
Hua Guo ◽  
Aleksander Jaworski ◽  
Zheng Chen ◽  
Can Lu ◽  
Adam Slabon ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
Transition Metal ◽  
Signal Intensity ◽  
Diffuse Reflectance ◽  
Conduction Band Edge ◽  
Vacancy Ordering ◽  
Vis Spectroscopy ◽  
O Vacancy ◽  
Barium Titanium

We investigated the nitridation of reduced BaTiO3, BaTiO2.60H0.08, corresponding to an oxyhydride with a large concentration of O defects (>10%). The material is readily nitrided under flowing N2 gas at temperatures between 400 and 450 °C to yield oxynitrides BaTiO2.6Nx (x = 0.2−0.22) with a slightly tetragonally distorted perovskite structure, a ≈ 4.01 and c ≈ 4.02 Å, and Ti partially remaining in the oxidation state III. The tetragonal structure was confirmed from Raman spectroscopy. 14N MAS NMR spectroscopy shows a single resonance at 270 ppm, which is typical for perovskite transition metal oxynitrides. However, largely different signal intensity for materials with very similar N content suggests N/O/vacancy ordering when prolonging nitridation times to hours. Diffuse reflectance UV-VIS spectroscopy shows a reduction of the intrinsic band gap to 2.4–2.45 eV compared to BaTiO3 (~3.2 eV). Mott-Schottky measurements confirm n-type conductivity and reveal a slight negative shift of the conduction band edge from –0.59 V (BaTiO3) to ~–0.65 eV.

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