Silver Exchange of Layered Metal Oxides and Their Photocatalytic Activities

ACS Catalysis ◽  
2013 ◽  
Vol 3 (11) ◽  
pp. 2547-2555 ◽  
Author(s):  
Jonathan Boltersdorf ◽  
Paul A. Maggard
Keyword(s):  
Metal Oxides ◽  
Photocatalytic Activities ◽  
Silver Exchange

scholarly journals Photocatalytic Applications of Metal Oxides for Sustainable Environmental Remediation

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 80
Author(s):  
Mir Sayed Shah Danish ◽  
Liezel L. Estrella ◽  
Ivy Michelle A. Alemaida ◽  
Anton Lisin ◽  
Nikita Moiseev ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Environmental Remediation ◽  
Cost Effective ◽  
Water Systems ◽  
Treatment Technology ◽  
Rapid Urbanization ◽  
Wide Range ◽  
Photocatalytic Activities ◽  
Nanoparticles Of Metal Oxides

Along with industrialization and rapid urbanization, environmental remediation is globally a perpetual concept to deliver a sustainable environment. Various organic and inorganic wastes from industries and domestic homes are released into water systems. These wastes carry contaminants with detrimental effects on the environment. Consequently, there is an urgent need for an appropriate wastewater treatment technology for the effective decontamination of our water systems. One promising approach is employing nanoparticles of metal oxides as photocatalysts for the degradation of these water pollutants. Transition metal oxides and their composites exhibit excellent photocatalytic activities and along show favorable characteristics like non-toxicity and stability that also make them useful in a wide range of applications. This study discusses some characteristics of metal oxides and briefly outlined their various applications. It focuses on the metal oxides TiO2, ZnO, WO3, CuO, and Cu2O, which are the most common and recognized to be cost-effective, stable, efficient, and most of all, environmentally friendly for a sustainable approach for environmental remediation. Meanwhile, this study highlights the photocatalytic activities of these metal oxides, recent developments, challenges, and modifications made on these metal oxides to overcome their limitations and maximize their performance in the photodegradation of pollutants.

scholarly journals Photocatalytic degradation of dyes in water by analytical reagent grades ZnO, TiO<sub>2</sub> and SnO<sub>2</sub>: a comparative study

2017 ◽  
Vol 10 (2) ◽  
pp. 109-117 ◽  
Author(s):  
Dnyaneshwar R. Shinde ◽  
Popat S. Tambade ◽  
Manohar G. Chaskar ◽  
Kisan M. Gadave
Keyword(s):  
Photocatalytic Activity ◽  
Metal Oxides ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Low Cost ◽  
Solar Irradiation ◽  
Degradation Of Dyes ◽  
Photocatalytic Activities ◽  
Analytical Reagent

Abstract. In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO2, and SnO2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO2, and SnO2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO2 and SnO2 as well as that of Degussa P-25 (TiO2). The photocatalytic dye decolourisation rates with ZnO were 1.14–1.35, 1.70–3.1, and 4–8.5 times higher than those of the Degussa P-25, TiO2, and SnO2, respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.

A comparative study on photocatalytic activities of various transition metal oxides nanoparticles synthesized by wet chemical route

2021 ◽  
Vol 211 ◽  
pp. 181-195
Author(s):  
Muhammad Farooq Warsi ◽  
Nusrat Shaheen ◽  
Muhammad Ilyas Sarwar ◽  
Philips O. Agboola ◽  
Imran Shakir ◽  
...  
Keyword(s):  
Transition Metal ◽  
Comparative Study ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Chemical Route ◽  
Photocatalytic Activities ◽  
Wet Chemical ◽  
Wet Chemical Route

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

Synthesis of ZnO/ZnFe2O4 nanocomposites in organic-free media and their photocatalytic activity under natural sunlight

2020 ◽  
Vol 14 (2) ◽  
pp. 6801-6810
Author(s):  
Rahmayeni Rahmayeni ◽  
Zulhadjri Zulhadjri ◽  
Yeni Stiadi ◽  
Agusnar Harry ◽  
Syukri Arief
Keyword(s):  
Electron Microscopy ◽  
Hexagonal Wurtzite Structure ◽  
Rice Grain ◽  
X Ray Diffraction ◽  
Homogeneous Sphere ◽  
Natural Sunlight ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Free Media ◽  
Photocatalytic Applications

Nanocomposite ZnO/ZnFe2O4 photocatalysts with different proportions of ZnFe2O4 were synthesized in organic-free media using metal nitric as precursors. The ZnO phase with hexagonal wurtzite structure and low crystallinity of ZnFe2O4 was confirmed using XRD (X-Ray diffraction). Different morphologies of the nanocomposites were obtained ranging from rice grain-like with a porous surface to homogeneous sphere-like nanoparticles as shown in Scanning Electron Microscopy (SEM) and TEM Transmission Electron Microscopy (TEM) studies. Magnetic properties measured by Visible Sampler Magnetometer (VSM) showed diamagnetic and paramagnetic behavior for the nanocomposites. Analysis with Diffuse Reflectance Spectrophotometer (DRS) UV-vis showed an increase the composition of ferrite in composites increasing its ability to absorb visible light. Photocatalytic activities of ZnO/ZnFe2O4 nanocomposites on the degradation of Rhodamine B dye reached 95.6% after 3 h under natural sunlight suggesting their suitability for sunlight driven photocatalytic applications. 

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.

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