Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Particle size determination transmission electron microscop

The Fe-B nanocomposite was synthesized by the so-called pillaring technique using layered bentonite clay as the starting material. The detailed procedures were described in our previous study [4]. X-ray diffraction (XRD) analysis revealed that the Fe-B nanocomposite mainly consists of Fc203 (hematite) and Si02 (quartz). The bulk Fe concentration of the Fe-B nanocomposite measured by a JOEL X-ray Reflective Fluorescence spectrometer (Model JSX 3201Z) is 31.8%. The Fe surface atomic concentration of Fe-B nanocomposite determined by an X-ray photoelectron spectrometer (Model PHI5600) is 12.25 (at%). The BET specific surface area is 280 m /g. The particle size determined by a transmission electron microscope (JOEL 2010) is from 20 to 200 nm. [Pg.389]

Nitrogen adsorption isotherms were measured with a sorbtometer Micromeretics Asap 2010 after water desorption at 130°C. The distribution of pore radius was obtained from the adsorption isotherms by the density functional theory. Electron microscopy study was carried out with a scanning electron microscope (SEM) HitachiS800, to image the texture of the fibers and with a transmission electron microscope (TEM) JEOL 2010 to detect and measure metal particle size. The distribution of particles inside the carbon fibers was determined from TEM views taken through ultramicrotome sections across the carbon fiber. [Pg.56]

The size of Ti-Beta particles was determined with the high resolution transmission electron microscope (HRTEM). After 28 hours of hydrothermal treatment they grew to... [Pg.67]

The useful range of the transmission electron microscope for particle size measurement is c. 1 nm-5 p,m diameter. Owing to the complexity of calculating the degree of magnification directly, this is usually determined by calibration using characterised polystyrene latex particles or a diffraction grating. [Pg.48]

To etch away silica, carbonization product samples were treated with a mixture of concentrated sulfuric and hydrofluoric acids (5 drops of H2S04 and 1 mL of HF), boiled dry and washed with water. From the precipitate obtained were prepared dispersions in acetone, which were used to determine the size and shape of particles on a JEM100CX-II transmission electron microscope by a commonly used procedure[10]. [Pg.522]

The bulk densities were calculated from weight and volume measurements. Skeletal densities were measured by He pycnometry N2 adsorption-desorption isotherms were determined at 77 K on a Carlo Erba Sorptomatic 1900 and their analysis was done using a set of well-known techniques [5], Mercury porosimetry up to a pressure of 200 MPa is performed on a Carlo Erba Porosimeter 2000. Samples were examined using a transmission electron microscope to obtain particle and aggregate sizes [2]. [Pg.179]

Average particle sizes were determined with TEM. For that purpose a drop of the colloidal solution was placed on a carbon covered copper grid (Balzers) and analyzed with a high resolution transmission electron microscope (model JEOL 200 CX). Particle size distributions were determined by optical inspection of the photographs. From this data, metal areas of the catalysts were estimated assuming spherical particle shape and a rhodium surface density of 1.66 10 mol Rh/m [10]. As a reference material for characterization and testing, a commercial rhodium on carbon catalyst (5w% Rh, Aldrich) was used. [Pg.322]

High resolution transmission electron microscopy (TEM) (Jeol lOOCX) was employed to determine the size of the metal particles on the surface of the catalyst support, and the composition of individual metal particles was ascertained (for thin sections cut with an ultramicrotome) using a field-emission scaiming transmission electron microscope (STEM) (VG HB 501) (at 1.5 mm resolution) and an energy dispersive X-ray (EDX) analyser. The metal loading of catalysts was determined by ICP-AES (Spectro D), following dissolution in concentrated hydrochloric and sulphuric acids. Direct analysis of aqueous samples taken from the reaction medium, using the same analytical technique, allowed the corrosion of metallic components from the catalyst surface to be studied. [Pg.430]

Transmission Electron Microscopy. A Philips model 201 (Arvada, CO) transmission electron microscope was used as an alternative method for determining the particle sizes of Ludox silicas. Specimens were prepared on formvar-coated, 200-mesh copper specimen grids. Typical acceleration voltages and magnifications were 80 kV and 65,000X. [Pg.313]

The catalysts were characterized by transmission electron microscope(TEM, Hitachi H9000UHR) operated at 300 kV for the direct observation of the particle size and the distribution of Mg species, X-ray photoelectron spectroscopy ( XPS, PHI Quanteta SXM) for the examination of surface Ce/Zr concentration and valence of Ce species, X-ray diffractometer (XRD, Rigaku RINT02000) operated at 30 kV and 20 m A for the determination of crystallite structures. [Pg.779]

Specific surface areas were determined by the BET method from the nitrogen adsorption at 77 K, using an automatic Micrometries ASAP 2000. Palladium metal dispersion was determined by the dynamic pulsed hydrogen chemisorption. The metallic average particle size of palladium was examined by a transmission electron microscope (JEOL 100 CX) with a resolution factor of 0.3 nm. Chemical analysis allowing the... [Pg.333]

The surface area can be calculated from particle size measured with transmission electron microscope (TEM) (ASTM D3849). Generally, for rubber grade, the surface areas determined by TEM are in reasonable agreement with surface areas determined by nitrogen adsorption measurements. However, for those carbon blacks that have highly developed micropores such as special pigment blacks and blacks used for electrical conductivity, the surface areas calculated from their particle diameters are smaller than those calculated from gas absorption, as the internal surface area in the micropore is excluded. [Pg.969]

Characterization. Transmission electron micrographs were taken with a JEOL-100 CX n transmission electron microscope in order to obtain the particle size, morphology, and particle size distribution of the sanq>les. The TEM samples were prepared by placing a drop of the colloid on a carbon-coated copper grid and letting the solvent evaporate. The particle sizes were measured with a conq)arator and the average particle sizes and size distributions were determined based on the measurement of at least 100 particles. [Pg.139]

All measurements are performed using the refractive index of CdS. In the case of cadmium sulfide nanoparticles produced in the w/o microemulsion the viscosity rj and the refractive index no of the continuous oil phase, namely the xylene-pentanol (1 1) mixture ( = 1.454 cP, D = 1165) are used. Consequently rj and no for water are used when the CdS nanoparticles are redispersed in the aqueous phase. Morphology and size of the redispersed CdS particles are also determined by transmission electron microscopy. Therefore, a small amount of the aqueous solutions is dropped on copper grids, dried and examined in the EM 902 transmission electron microscope (Zeiss) (acceleration voltage 90 kV). The high amount of surfactant brings also difficulties for the preparation of the samples for TEM measurements and consequently samples have to be washed with water to reduce the amount of surfactant. [Pg.150]

A JEOL JEM-100 CX II transmission electron microscope (TEM) was used to assess the particle size and shape. The sample was deposited on a Formvar film-coated carrier grid. The size distribution of the sample was determined by measuring the diameters of around 500 spherical particles. For demonstration, a TEM image of the particles is shown in Fig. 1. The size distribution of the sample investigated (average diameter of 44 nm) is depicted in Fig. 2. ... [Pg.55]

Transmission electron micrographs were made with a Philips CM-10 transmission electron microscope with an accelerating voltage of 100 kV. The particle size distribution was determined by using the UTHSCSA Image Tool program. [Pg.90]


See other pages where Particle size determination transmission electron microscop is mentioned: [Pg.151]    [Pg.875]    [Pg.464]    [Pg.45]    [Pg.322]    [Pg.163]    [Pg.313]    [Pg.377]    [Pg.154]    [Pg.85]    [Pg.305]    [Pg.371]    [Pg.87]    [Pg.370]    [Pg.389]    [Pg.21]    [Pg.337]    [Pg.668]    [Pg.121]    [Pg.40]    [Pg.882]    [Pg.131]    [Pg.158]    [Pg.571]    [Pg.124]    [Pg.743]    [Pg.404]    [Pg.971]    [Pg.409]    [Pg.83]    [Pg.157]    [Pg.4930]   
See also in sourсe #XX -- [ Pg.118 ]




SEARCH



Electron microscop

Electron microscope

Electron microscopic

Electronic particle sizing

Microscopes electron microscope

Particle determination

Particle size determination

Particle size determining

Particle size microscopic

Particles electrons

Particles, transmission electron

Size determinations

© 2024 chempedia.info