scholarly journals Lewis Acid Site and Hydrogen-Bond-Mediated Polarization Synergy in the Catalysis of Diels–Alder Cycloaddition by Band-Gap Transition-Metal Oxides

ACS Catalysis ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 701-715 ◽  
Author(s):  
Taha Salavati-fard ◽  
Efterpi S. Vasiliadou ◽  
Glen R. Jenness ◽  
Raul F. Lobo ◽  
Stavros Caratzoulas ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transition Metal ◽  
Metal Oxides ◽  
Band Gap ◽  
Lewis Acid ◽  
Transition Metal Oxides ◽  
Acid Site ◽  
Lewis Acid Site ◽  
Diels Alder

P-type doping of organic wide band gap materials by transition metal oxides: A case-study on Molybdenum trioxide

2009 ◽  
Vol 10 (5) ◽  
pp. 932-938 ◽  
Author(s):  
Michael Kröger ◽  
Sami Hamwi ◽  
Jens Meyer ◽  
Thomas Riedl ◽  
Wolfgang Kowalsky ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Band Gap ◽  
Transition Metal Oxides ◽  
Molybdenum Trioxide ◽  
Wide Band ◽  
Wide Band Gap ◽  
P Type

Density Functional Theory and Beyond for Band-Gap Screening: Performance for Transition-Metal Oxides and Dichalcogenides

2013 ◽  
Vol 9 (7) ◽  
pp. 2950-2958 ◽  
Author(s):  
Wenqing Li ◽  
Christian F. J. Walther ◽  
Agnieszka Kuc ◽  
Thomas Heine
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Metal Oxides ◽  
Band Gap ◽  
Transition Metal Oxides ◽  
Density Functional ◽  
Functional Theory ◽  
Screening Performance

Surface Band Gaps and Superexchange Interaction in Transition Metal Oxides

1995 ◽  
Vol 401 ◽  
Author(s):  
J. J. M. Pothuizen ◽  
O. Cohen ◽  
G. A. Sawatzky
Keyword(s):  
Charge Transfer ◽  
Transition Metal ◽  
Metal Oxides ◽  
Band Gap ◽  
Transition Metal Oxides ◽  
Band Gaps ◽  
Superexchange Interaction ◽  
Surface Band ◽  
Madelung Potential

AbstractIn this paper, we discuss the change in the band gap of charge transfer insulators for different surface terminations. We have calculated the Madelung potential of the unreconstructed (100) surfaces of the rocksalt structured TM-O compounds (TM = Mn, Fe, Co and Ni). We also considered possible step defects on a (100) surface. The presented results are calculated in both the purely ionic case (TM2+O2−) and in the strong ligand p - cation 4s, phybridization (TM1+O1−) case. In both cases the charge transfer gap, Δ, for the surface is reduced compared to the bulk value. As a consequence of this reduction there is a large increase of the surface superexchange interaction, Jsur, and a decrease of the band gap.

scholarly journals Crystal-seeds induced construction of ZnO–ZnFe2O4 micro-cubic composites as excellent anode materials for lithium ion battery

RSC Advances ◽  
2018 ◽  
Vol 8 (29) ◽  
pp. 16187-16192 ◽  
Author(s):  
Pei Pan ◽  
Ting Wang ◽  
Lihui Chen ◽  
Feng Wang ◽  
Xiong Yang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electrochemical Performance ◽  
Metal Oxides ◽  
Band Gap ◽  
Transition Metal Oxides ◽  
Anode Materials ◽  
Lithium Ion ◽  
Band Gap Energy ◽  
Hetero Structure ◽  
Gap Energy

This work aims at designing a fine assembly of two different transition metal oxides with a distinct band-gap energy into a bi-component-active hetero-structure to improve electrochemical performance.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

Problems with oxygen analysis in the system MgO-Al2O3-SiO2 with the electron microprobe

1992 ◽  
Vol 50 (2) ◽  
pp. 1624-1625
Author(s):  
Michel Fialin ◽  
Guy Rémond
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Electrostatic Charge ◽  
Carbon Layer ◽  
Sample Holder ◽  
Rock Matrix ◽  
Electrical Discharges ◽  
Thin Carbon ◽  
Beam Instabilities

Oxygen-bearing minerals are generally strong insulators (e.g. silicates), or if not (e.g. transition metal oxides), they are included within a rock matrix which electrically isolates them from the sample holder contacts. In this respect, a thin carbon layer (150 Å in our laboratory) is evaporated on the sections in order to restore the conductivity. For silicates, overestimated oxygen concentrations are usually noted when transition metal oxides are used as standards. These trends corroborate the results of Bastin and Heijligers on MgO, Al2O3 and SiO2. According to our experiments, these errors are independent of the accelerating voltage used (fig.l).Owing to the low density of preexisting defects within the Al2O3 single-crystal, no significant charge buildup occurs under irradiation at low accelerating voltage (< 10keV). As a consequence, neither beam instabilities, due to electrical discharges within the excited volume, nor losses of energy for beam electrons before striking the sample, due to the presence of the electrostatic charge-induced potential, are noted : measurements from both coated and uncoated samples give comparable results which demonstrates that the carbon coating is not the cause of the observed errors.

CVD - technology of transition metal oxides and their impact on solar energy utilization

1993 ◽  
Vol 03 (C3) ◽  
pp. C3-475-C3-483 ◽  
Author(s):  
K. A. GESHEVA ◽  
D. S. GOGOVA
Keyword(s):  
Transition Metal ◽  
Solar Energy ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Energy Utilization ◽  
Solar Energy Utilization

Lewis Acid Site-Promoted Single-Atomic Cu Catalyzes Electrochemical CO2 Methanation

Nano Letters ◽  
2021 ◽  
Author(s):  
Shenghua Chen ◽  
Bingqing Wang ◽  
Jiexin Zhu ◽  
Liqiang Wang ◽  
Honghui Ou ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Acid Site ◽  
Lewis Acid Site ◽  
Co2 Methanation
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