Mechanism of acidity generation on sulfur-promoted metal oxides

1986 ◽  
Vol 90 (20) ◽  
pp. 4794-4796 ◽  
Author(s):  
Tuo Jin ◽  
Tsutomu Yamaguchi ◽  
Kozo Tanabe
Keyword(s):  
Metal Oxides ◽  
Acidity Generation

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.

METAL-OXIDES COMPOSITES FOR BaFe12O19 PERMANENT MAGNETS

1977 ◽  
Vol 38 (C1) ◽  
pp. C1-333-C1-336 ◽  
Author(s):  
P. CAVALLOTTI ◽  
R. ROBERTI ◽  
G. CAIRONI ◽  
G. ASTI
Keyword(s):  
Metal Oxides ◽  
Permanent Magnets

Influence of the Polarization of Molecules of Metal Oxides on the Diffusion Coefficient in Smoky Plasmas

2014 ◽  
Vol 59 (4) ◽  
pp. 401-404
Author(s):  
G.S. Dragan ◽  
◽  
K.V. Kolesnikov ◽  
V.M. Ulianytskyi ◽  
◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Metal Oxides

Acalypha Indica mediated MgO NPs: A novel approach in greener route with its antibacterial activity against pathogens

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Kavipriya K C ◽  
Sudha A P ◽  
Sujatha K ◽  
Sowmya Lakshmi K
Keyword(s):  
Antibacterial Activity ◽  
Metal Oxides ◽  
Bacterial Species ◽  
Magnesium Nitrate ◽  
Precipitation Method ◽  
Average Crystalline Size ◽  
Face Centered Cubic ◽  
X Ray ◽  
Novel Approach ◽  
Acalypha Indica

The interest in miniaturization of particles revealed the hidden applications of metal oxides. The potential applications of the particles may vary when the size of the particle is reduced. One of the alternative routes to the conventional approach is the use of plant extract for the synthesis of metal oxides NPs. In the framework of this study, the ecofriendly MgO nanoparticles were synthesized using Acalypha Indica leaf extract,functioning as reducing and capping agent by co-precipitation method. The predecessor taken here was Magnesium Nitrate. The biologically synthesized MgO NPs were characterized by various techniques like X ray diffraction(XRD), Fourier Transform infrared spectroscopy(FTIR), Scanning electron microscope (SEM) with Energy Dispersive X-ray spectroscopy(EDX) profile and its antibacterial activity is evaluated against causative organisms. XRD studies confirmed the face centered cubic crystalline structure of MgO NPs and the average crystalline size of MgO NPs calculated using Scherer’s formula was found to be 13 nm. FTIR spectrum shows a significant Mg-O vibrational band. Purity, surface morphology and chemical composition of elements were confirmed by SEM with EDX. The SEM result shows the fine spherical morphology with the grain size range between 43nm to 62nm. Antimicrobial assay of MgO NPs was examined against gram positive and negative bacteria. Appreciated activity was observed on the Staphylococcus aureus bacterial species. In general, the renewed attempt of this facile approach gave the optimum results of multifunctional MgO NPs.

Interface Studies of Metal Oxides Grown Directly on Hybrid Perovskite by Atomic Layer Deposition

2019 ◽  
Author(s):  
Claire Burgess ◽  
Farzad Mardekatani Asl ◽  
Valerio Zardetto ◽  
Herbert Lifka ◽  
Sjoerd Veenstra ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Metal Oxides ◽  
Atomic Layer ◽  
Hybrid Perovskite ◽  
Layer Deposition

A New Method for Obtaining Nanodimensional Powders of Metal Oxides

2018 ◽  
Vol 482 (2) ◽  
pp. 160-162
Author(s):  
G. Panasiuk ◽  
◽  
E. Semenov ◽  
I. Kozerozhets ◽  
Kh. Yorov ◽  
...  
Keyword(s):  
Metal Oxides ◽  
New Method
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