Initial Reduction of the PdO(101) Surface: Role of Oxygen Vacancy Formation Kinetics

2018 ◽  
Vol 122 (45) ◽  
pp. 26007-26017 ◽  
Author(s):  
Minkyu Kim ◽  
Li Pan ◽  
Jason F. Weaver ◽  
Aravind Asthagiri
Keyword(s):  
Oxygen Vacancy ◽  
Vacancy Formation ◽  
Formation Kinetics ◽  
Initial Reduction ◽  
Oxygen Vacancy Formation

scholarly journals Activation of Water on MnOx-Modified Rutile (110) and Anatase (101) TiO2 and the Role of Cation Reduction

2018 ◽  
Author(s):  
Michael Nolan ◽  
Stephen Rhatigan
Keyword(s):  
Oxygen Vacancy ◽  
Light Absorption ◽  
Density Functional ◽  
Vacancy Formation ◽  
Visible Range ◽  
Coulomb Interactions ◽  
Carrier Recombination ◽  
Oxygen Vacancy Formation ◽  
Surface Hydroxyls

Surface modification of titania surfaces with dispersed metal oxide nanoclusters has the potential to enhance photocatalytic activity. These modifications can induce visible light absorption and suppress charge carrier recombination which are vital in improving the efficiency. We have studied heterostructures of Mn<sub>4</sub>O<sub>6</sub> nanoclusters modifying the TiO<sub>2</sub> rutile (110) and anatase (101) surfaces using density functional theory corrected for on-site Coulomb interactions (DFT + U). Such studies typically focus on the pristine surface, free of the point defects and surface hydroxyls present in real surfaces. In our study we have considered partial hydroxylation of the rutile and anatase surfaces and the role of cation reduction, via oxygen vacancy formation, and how this impacts on a variety of properties governing the photocatalytic performance such as nanocluster adsorption, light absorption, charge separation and reducibility. Our results indicate that the modifiers adsorb strongly at the surface and that modification extends light absorption into the visible range. MnO<sub>x</sub>-modified anatase can show an off-stoichiometric ground state, through oxygen vacancy formation and cation reduction spontaneously, and both modified rutile and anatase are highly reducible with moderate energy costs. Manganese ions are therefore present in a mixture of oxidation states. Photoexcited electrons and holes localize at cluster metal and oxygen sites, respectively. The interaction of water at the modified surfaces depends on the stoichiometry and spontaneous dissociation to surface bound hydroxyls is favoured in the presence of oxygen vacancies and reduced metal cations. Comparisons with bare TiO<sub>2</sub> and other TiO<sub>2</sub>-based photocatalyst materials are presented throughout.

scholarly journals Activation of Water on MnOx-Modified Rutile (110) and Anatase (101) TiO2 and the Role of Cation Reduction

2018 ◽  
Author(s):  
Michael Nolan ◽  
Stephen Rhatigan
Keyword(s):  
Oxygen Vacancy ◽  
Light Absorption ◽  
Density Functional ◽  
Vacancy Formation ◽  
Visible Range ◽  
Coulomb Interactions ◽  
Carrier Recombination ◽  
Oxygen Vacancy Formation ◽  
Surface Hydroxyls

Surface modification of titania surfaces with dispersed metal oxide nanoclusters has the potential to enhance photocatalytic activity. These modifications can induce visible light absorption and suppress charge carrier recombination which are vital in improving the efficiency. We have studied heterostructures of Mn<sub>4</sub>O<sub>6</sub> nanoclusters modifying the TiO<sub>2</sub> rutile (110) and anatase (101) surfaces using density functional theory corrected for on-site Coulomb interactions (DFT + U). Such studies typically focus on the pristine surface, free of the point defects and surface hydroxyls present in real surfaces. In our study we have considered partial hydroxylation of the rutile and anatase surfaces and the role of cation reduction, via oxygen vacancy formation, and how this impacts on a variety of properties governing the photocatalytic performance such as nanocluster adsorption, light absorption, charge separation and reducibility. Our results indicate that the modifiers adsorb strongly at the surface and that modification extends light absorption into the visible range. MnO<sub>x</sub>-modified anatase can show an off-stoichiometric ground state, through oxygen vacancy formation and cation reduction spontaneously, and both modified rutile and anatase are highly reducible with moderate energy costs. Manganese ions are therefore present in a mixture of oxidation states. Photoexcited electrons and holes localize at cluster metal and oxygen sites, respectively. The interaction of water at the modified surfaces depends on the stoichiometry and spontaneous dissociation to surface bound hydroxyls is favoured in the presence of oxygen vacancies and reduced metal cations. Comparisons with bare TiO<sub>2</sub> and other TiO<sub>2</sub>-based photocatalyst materials are presented throughout.

scholarly journals Oxygen vacancy formation energies in PbTiO3/SrTiO3 superlattice

2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Lipeng Zhang ◽  
Isaac Bredeson ◽  
Axiel Y. Birenbaum ◽  
P. R. C. Kent ◽  
Valentino R. Cooper ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Vacancy Formation ◽  
Oxygen Vacancy Formation ◽  
Formation Energies

Correlation between crystallinity and oxygen vacancy formation in In–Ga–Zn oxide

2016 ◽  
Vol 55 (2) ◽  
pp. 021203 ◽  
Author(s):  
Tomoki Hiramatsu ◽  
Motoki Nakashima ◽  
Erumu Kikuchi ◽  
Noritaka Ishihara ◽  
Masashi Tsubuku ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Vacancy Formation ◽  
Oxygen Vacancy Formation

Factors Governing Oxygen Vacancy Formation in Oxide Perovskites

2021 ◽  
Author(s):  
Robert B. Wexler ◽  
Gopalakrishnan Sai Gautam ◽  
Ellen B. Stechel ◽  
Emily A. Carter
Keyword(s):  
Oxygen Vacancy ◽  
Vacancy Formation ◽  
Oxygen Vacancy Formation
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