Nanopowders of Metallic Oxides Prepared by the Hydrolytic Route with Starch Stabilization and Biological Abetment

2006 ◽  
Vol 6 (1) ◽  
pp. 254-257 ◽  
Author(s):  
Emanuela Callone ◽  
Giovanni Carturan ◽  
Adriana Sicurelli
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Differential Thermal Analysis ◽  
Specific Surface ◽  
Evidence Based ◽  
X Ray ◽  
Metallic Oxides ◽  
Transmission Electron

Sn, Sn–Sb, Ti, Zr, Fe, Ce and In oxides are prepared as nanometric powders by the hydrolytic route, starting from their ordinary salts or alkoxides, in the presence of 5% w/v starch as a non-ionic stabilizer of crystallization nuclei versus coalescence and flocculation. The starch can be degraded by α-amylase to soluble glucosidic oligomers, which may further be degraded by yeast to CO2 and ethanol. The nanoparticle features of prepared oxides result from experimental evidence based on X-ray diffractometry, transmission electron microscopy, differential thermal analysis/thermogravimetry coupled to mass spectrometry, specific surface area and porosity of samples obtained by curing in the 80–600 °C interval.

Preparation and Photocatalysis of Nano-Zn/Ce Composite Oxides

2014 ◽  
Vol 67 (4) ◽  
pp. 657 ◽  
Author(s):  
Xiuping Li ◽  
Yuchun Zhai ◽  
Peihua Ma ◽  
Rongxiang Zhao
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Differential Thermal Analysis ◽  
Precipitation Method ◽  
Diffraction Field ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Metal oxide photocatalysts often lead to partial or complete mineralization of organic pollutants. On irradiation with UV-visible light, metal oxides catalyze redox reactions in the presence of air and O2 and water. Using ascorbic acid as a new combustion agent, ZnO was rapidly synthesized. Nano-Zn/CeO2 composites were prepared by a heterogeneous-precipitation method using (NH4)2CO3 as precipitation agent. X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectrometry, ultraviolet spectrophotometry, and differential thermal analysis were used to analyse the microstructures of the synthesized materials. Differential thermal analysis, transmission electron microscopy, and X-ray diffraction analyses indicated that ZnO was coated by CeO2. Herein, a nano-Zn/Ce composite was explored as a catalyst for Rhodamine B photodegradation with a 125-W lamp as the UV radiation source in a batch reactor. The results show the photocatalytic properties of the nano-Zn/Ce composite were superior to ZnO, CeO2, and nano-Ce/Zn composites.

Identification of pseudoboehmite in mixtures with phyllosilicates

Clay Minerals ◽  
1994 ◽  
Vol 29 (3) ◽  
pp. 351-359 ◽  
Author(s):  
A. Violante ◽  
P. M. Huang
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Differential Thermal Analysis ◽  
Detection Limit ◽  
Clay Minerals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Oriented Samples

AbstractThe influence of kaolinite and montmorillonite on the identification of pseudoboehmite was studied by X-ray diffraction (XRD), differential thermal analysis (DTA), infrared absorption (IR), and transmission electron microscopy (TEM). In the randomly oriented samples containing different proportions of the clay minerals and pseudoboehmite, pseudoboehmite was not easily detectable by XRD even in a sample containing 40% of pseudoboehmite. Preheating of the samples at 110-300°C improved the detection limit to 30%. In samples obtained by mixing suitable amounts of the suspensions of the clay minerals (<2μm)and pseudoboehmite, the identification of pseudoboehmite was even more difficult. In oriented samples, pseudoboehmite was detectable only when present in amounts >30%, at low full-scale counts per second (1000-400 cps), on preheated samples in the presence of kaolinite, or on the samples that were Mg-saturated and solvated with ethylene glycol in the presence of montmorillonite. Identification of pseudoboehmite in the presence of kaolinite or montmorillonite by DTA, IR or TEM failed, even in samples containing 50% pseudoboehmite. In the presence of both kaolinite and montmorillonite (1:1 w/w), the identification of pseudoboehmite became much more difficult than in the presence of either mineral alone. The presence of pseudoboehmite in soils may, thus, be undetectable by standard clay mineralogical analyses.

On the destruction of kaolinite and gibbsite by phenylphosphonic, phenylphosphinic and phenylarsonic acids: evidence for the formation of new Al compounds

Clay Minerals ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 391-404 ◽  
Author(s):  
J. E. F. C. Gardolinski ◽  
G. Lagaly ◽  
M. Czank
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Linear Chain ◽  
X Ray Diffraction ◽  
Phenylphosphonic Acid ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron

AbstractKaolinite and synthetic γ-Al(OH)3 (gibbsite or hydrargillite) were reacted with phenylphosphonic, phenylphosphinic and 2-nitrophenol-4-arsonic acids. The products were studied by powder X-ray diffraction, transmission electron microscopy/selected area electron diffraction/ energy dispersive X-ray/Fourier transform infrared and simultaneous thermogravimetric/differential thermal analysis. The acids were not intercalated but, instead, easily destroyed the structure of the minerals. Lamellar Al phenylphosphonate and aluminium phenylphosphinate and phenylarsonate with polymeric linear-chain structures were formed from kaolinite. The reaction between gibbsite and the same acids yielded almost identical products. No evidence of formation of grafted kaolinite derivatives after the reaction with phenylphosphonic acid was found.

Lack of a threefold rotation axis in α-Fe2O3and α-Cr2O3crystals

2015 ◽  
Vol 71 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Michał Stękiel ◽  
Radosław Przeniosło ◽  
Izabela Sosnowska ◽  
Andrew Fitch ◽  
Jacek B. Jasiński ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rotation Axis ◽  
Magnetic Ordering ◽  
Evidence Based ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
Transmission Electron

The crystal structure of α-Fe2O3and α-Cr2O3is usually described with the corundum-type trigonal crystal structure based on the space group R\bar 3c. There are, however, some observations of the magnetic ordering of both α-Fe2O3and α-Cr2O3that are incompatible with the trigonal symmetry. We show experimental evidence based on X-ray powder diffraction and supported by transmission electron microscopy that the symmetry of the crystal structure of both α-Fe2O3and α-Cr2O3is monoclinic and it is described with the space groupC2/c(derived from R\bar 3c by removing the threefold rotation axis). The magnetic orderings of α-Fe2O3and α-Cr2O3are compatible with the magnetic space groupsC2/candC2/c′, respectively. These findings are in agreement with the idea from Curie [(1894),J. Phys.3, 393–415] that the dissymmetry of the magnetic ordering should be associated with a dissymmetry of the crystal structure.

Preparation of Carbon-Encapsulated Fe Core-Shell Nanostructures by Confined Arc Plasma

2011 ◽  
Vol 688 ◽  
pp. 245-249 ◽  
Author(s):  
Zhi Qiang Wei ◽  
Xiao Yun Wang ◽  
Hua Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Core Shell ◽  
Arc Plasma ◽  
X Ray ◽  
The Core ◽  
Transmission Electron

Special carbon encapsulated Fe core-shell nanoparticles with a size range of 15–40 nm were successfully prepared via confined arc plasma method. The composition, morphology, microstructure, specific surface area, particle size of the product by this process were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS) and BET N2adsorption. The experiment results shown that the carbon encapsulated Fe nanoparticles with clear core-shell structure, the core of the particles is body centered cubic (BCC) structure Fe, and the shell of the particles is disorder carbons. The particle size of the nanocapsules ranges from 15 to 40nm，with an averaged value about 30nm, the particles diameter of the core is about 16nm and the thickness of the shells is about 6-8 nm, and the specific surface area is 24 m2/g.

New Synthetic Pathways to Mesostructured Thiogermanates

1998 ◽  
Vol 547 ◽  
Author(s):  
N. Oberender ◽  
M. Fröba
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Absorption Spectroscopy ◽  
Powder Diffraction ◽  
Metal Chalcogenides ◽  
Templated Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
X Ray Absorption

AbstractThe synthesis and characterisation of several mesostructured thiogermanates are shown. In particular the first supramolecular templated synthesis of mesostructured binary metal chalcogenides in a microwave is presented. The obtained products are characterised by x-ray powder diffraction, transmission electron microscopy, thermal analysis and x-ray absorption spectroscopy.

Facile Removal of Pesticides from Aqueous Solutions Using Magnetic Nanocomposites I. Synthesis and characterization of the adsorbent material

2019 ◽  
Vol 70 (11) ◽  
pp. 3931-3934
Author(s):  
Irina Fierascu ◽  
Raluca Somoghi ◽  
Cristian Andi Nicolae ◽  
Nicolae Stanica ◽  
Radu Claudiu Fierascu
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Aqueous Solutions ◽  
Synthesis And Characterization ◽  
Magnetic Nanocomposites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

An inorganic/organic magnetic nanocomposite was synthesized and analytically characterized using X-ray fluorescence, X-ray diffraction, transmission electron microscopy and thermal analysis. The evaluation of the magnetic properties revealed that both the magnetite and the magnetite/chitosan nanocomposite are superparamagnetic with a paramagnetic component, having the saturation magnetization values of 48.04 emu/g, and 41.3 emu/g, respectively. The synthesized material is indented for the adsorption of two known commercial-available pesticides (active ingredients deltamethrin and thiamethoxam, respectively) from aqueous solutions.

Characteristics of Nanosize Sn Powder Prepared by Spark Processing

2006 ◽  
Vol 326-328 ◽  
pp. 397-400
Author(s):  
Sung Sik Chang ◽  
Hye Jeong Park ◽  
Akira Sakai
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Differential Thermal Analysis ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Average Size ◽  
Calculated Average

The spark processing of metallic Sn yields a powder, which is a mixture of nanosize Sn and crystalline SnO2. This paper reports the characteristics of nanosize Sn powders. Scanning tunneling microscopy (STM) and transmission electron microscopy (TEM) studies reveal an existence of spherical shaped nanocrystals ranging from 2 to 5 nm in size. In contrast the measured surface area of spark processed Sn (sp-Sn) powders by BET is 27.7 m2/g and calculated average size of sp- Sn is about 31 nm, which is close to one order of magnitude larger than the observed size. Further, the characteristics of sp-Sn powders are studied by Raman, and differential thermal analysis (DTA).

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