Anchoring Sites for Initial Au Nucleation on CeO2{111}: O Vacancy versus Ce Vacancy

2009 ◽  
Vol 113 (16) ◽  
pp. 6411-6417 ◽  
Author(s):  
Changjun Zhang ◽  
Angelos Michaelides ◽  
David A. King ◽  
Stephen J. Jenkins
Keyword(s):  
Vacancy Versus ◽  
O Vacancy

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.

“Bi–O” vacancy-pairs induced photochromic behavior in Bi2WO6 ultrathin nanosheets

2021 ◽  
Vol 223 ◽  
pp. 110988
Author(s):  
Pan Zhang ◽  
Yuanyuan Cui ◽  
Yongji Yao ◽  
Wei Wei ◽  
Yuanyuan Sun ◽  
...  
Keyword(s):  
Photochromic Behavior ◽  
Ultrathin Nanosheets ◽  
O Vacancy

Visible light stimulating dual-wavelength emission and O vacancy involved energy transfer behavior in luminescence for coaxial nanocable arrays

2014 ◽  
Vol 115 (22) ◽  
pp. 224308 ◽  
Author(s):  
Lei Yang ◽  
Jiazhang Dong ◽  
Zhongcheng Jiang ◽  
Anlian Pan ◽  
Xiujuan Zhuang
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Dual Wavelength ◽  
Transfer Behavior ◽  
Wavelength Emission ◽  
O Vacancy

Preferential location of zirconium dopants in cerium dioxide nanoparticles and the effects of doping on their reducibility: a DFT study

2020 ◽  
Vol 22 (45) ◽  
pp. 26568-26582
Author(s):  
Iskra Z. Koleva ◽  
Hristiyan A. Aleksandrov ◽  
Konstantin M. Neyman ◽  
Georgi N. Vayssilov
Keyword(s):  
Cerium Dioxide ◽  
Dft Study ◽  
Vacancy Formation ◽  
Ceria Nanoparticles ◽  
Zirconium Doping ◽  
Mixed Nanoparticles ◽  
O Vacancy ◽  
Preferential Location

Zirconium doping dramatically facilitates O vacancy formation in ceria nanoparticles not only at the surface but also in four-coordinated inner O positions, which enhances O mobility. In mixed nanoparticles zirconium tends to occupy inner sites.

Ab initiocalculations for the neutral and charged O vacancy in sapphire

1997 ◽  
Vol 56 (12) ◽  
pp. 7277-7284 ◽  
Author(s):  
Yong-Nain Xu ◽  
Zhong-Quan Gu ◽  
Xue-Fu Zhong ◽  
W. Y. Ching
Keyword(s):  
O Vacancy

Ab Initio Studies of Nb Doping Effect on the Formation and Diffusion of Oxygen Vacancy and Ti Interstitial in Rutile TiO2

2011 ◽  
Vol 304 ◽  
pp. 142-147 ◽  
Author(s):  
Xu Wang ◽  
Fu He Wang
Keyword(s):  
Activation Energy ◽  
Oxygen Vacancy ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Formation Energy ◽  
Suppressive Effect ◽  
Nb Doping ◽  
O Vacancy ◽  
And Migration ◽  
And Diffusion

The effect of Nb doping on the formation and diffusion of O vacancies and interstitial Ti in rutile TiO2 are studied by the use of ab initio density-functional calculations. Our calculation showed that the activation energy for the diffusion of O vacancy with Nb doping is higher than that of pure. That owing to suppressive effect of Nb doping on the formation of O vacancy. Different from the effect of Nb doping on O vacancy, both of the formation energy and migration barrier of interstitial Ti increase with the Nb doping. Our calculated results may be one of the reasons why Nb doping can improve oxidation resistance of γ-TiAl.

Structure, electric, elastic and optical properties of Mn2+-doped MgAl2O4 spinel with/without an O-vacancy

2018 ◽  
Vol 547 ◽  
pp. 111-119 ◽  
Author(s):  
Miao Wan ◽  
Kaihua He ◽  
Hanlie Hong ◽  
Qingbo Wang ◽  
Qili Chen
Keyword(s):  
Optical Properties ◽  
Mgal2o4 Spinel ◽  
O Vacancy

scholarly journals Formation of Periodic Arrays of O Vacancy Clusters on Monolayer FeO Islands Grown on Pt(111)

2010 ◽  
Vol 31 (8) ◽  
pp. 1013-1018 ◽  
Author(s):  
Teng MA ◽  
Qiang FU ◽  
Yunxi YAO ◽  
Yi CUI ◽  
Dali TAN ◽  
...  
Keyword(s):  
Vacancy Clusters ◽  
Periodic Arrays ◽  
O Vacancy

Interaction between atomic hydrogen and YBa2Cu3O7

1992 ◽  
Vol 7 (11) ◽  
pp. 2908-2915 ◽  
Author(s):  
Angel L.G. Ponce ◽  
Jose J. Fripiat
Keyword(s):  
Induction Period ◽  
Atomic Hydrogen ◽  
Dissociative Chemisorption ◽  
Experimental Conditions ◽  
Reaction Proceeds ◽  
Order Of Magnitude ◽  
O Vacancy ◽  
The Creation ◽  
Approximate Limit

Atomic hydrogen obtained from dissociative chemisorption of molecular H2 on Pt particles deposited on the surface of YBa2Cu3O7 reacts with the oxide in producing O vacancies and intercalating H at 82 °C under a H2 pressure of about 400 Torr. An induction period which extends over 1 h is observed as long as the concentration in O vacancies is below 0.1. Above this approximate limit the reaction proceeds quickly until about 1 mol H2 has been consumed. It then slows down progressively, but it is not completed even after 27 h of reaction and ∼1.4 H2 consumed, under these experimental conditions. The enthalpy for the creation of the O vacancy is 143 kcal/g mol O, while the H intercalation enthalpy is −57.5 kcal/g mol H. It appears that the reaction of molecular H2 over YBa2Cu3O7 not coated with Pt proceeds similarly, but the rate is nearly one order of magnitude slower, under identical conditions. The stoichiometry of the reaction agrees with the earlier suggestion that O1 is a labile oxygen which can be replaced by intercalated H. This site and the interstitial vacant sites in the copper chains square plane would be the first ones to be occupied by intercalated H.

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