Preparation and characterization of porous TiO2-SiO2 mixed oxide

2004 ◽  
Vol 848 ◽  
Author(s):  
Ang Thiam Peng ◽  
Zhong Ziyi ◽  
James Highfield
Keyword(s):  
Electron Microscopy ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Structural Information ◽  
High Surface ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Surface Areas ◽  
Transmission Electron

ABSTRACTA study on the comparison of porous TiO2-SiO2 mixed oxides synthesized variously via the “amine directed” method is reported. The amine capping groups were octylamine, dodecylamine, octyldecylamine, aniline, and isobutylamine. The mixed oxide is characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Brunauer-Emmett-Teller analysis (BET). While XRD, SEM and TEM provide mainly (bulk) structural information on the mixed oxide preparations, BET (N2 physisorption) probes into their surface area and texture. IR evidence suggests that intimate chemical mixing of both oxides has occurred, while BET measurements show that high surface areas are attainable and that the mixed oxide is more thermally stable than pure (control) samples of TiO2.

scholarly journals Structure of Carbon Materials Explored by Local Transmission Electron Microscopy and Global Powder Diffraction Probes

2018 ◽  
Vol 4 (4) ◽  
pp. 68 ◽  
Author(s):  
Karolina Jurkiewicz ◽  
Mirosława Pawlyta ◽  
Andrzej Burian
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Neutron Diffraction ◽  
Carbon Materials ◽  
Structural Information ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Local Transmission

Transmission electron microscopy and neutron or X-ray diffraction are powerful techniques available today for characterization of the structure of various carbon materials at nano and atomic levels. They provide complementary information but each one has advantages and limitations. Powder X-ray or neutron diffraction measurements provide structural information representative for the whole volume of a material under probe but features of singular nano-objects cannot be identified. Transmission electron microscopy, in turn, is able to probe single nanoscale objects. In this review, it is demonstrated how transmission electron microscopy and powder X-ray and neutron diffraction methods complement each other by providing consistent structural models for different types of carbons such as carbon blacks, glass-like carbons, graphene, nanotubes, nanodiamonds, and nanoonions.

High Surface Area Silicon Carbide Doped with Zirconium for use as Heterogeneous Catalyst Support

1996 ◽  
Vol 454 ◽  
Author(s):  
Marc J. Ledoux ◽  
Cuong Pham-Huu ◽  
Christophe Bouchy ◽  
Pascal Del Gallo ◽  
Claude Estournes ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Area ◽  
High Surface ◽  
Catalyst Support ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Bet Method ◽  
Porosity Measurements

ABSTRACTHigh surface area (> 100 m2 · g−1) SiC doped with zirconium was prepared by the gas-solid reaction. The material was made up of three phases: β-SiC, covered by ZrO2 and an amorphous phase composed of Si, Zr and O. The characterization of the sample was performed by means of powder X-ray diffraction (XRD), surface area and porosity measurements by the BET method, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Preliminary catalytic tests, the standard n-C7 isomerization on supported MoOxCy showed that this new support was at least as effective as pure SiC.

Dispersion and improvement of organoclays in nanocomposites based on poly(propylene oxide)

2020 ◽  
pp. 089270572093917 ◽  
Author(s):  
Lahouari Mrah ◽  
Rachid Meghabar
Keyword(s):  
Electron Microscopy ◽  
Propylene Oxide ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
The Matrix ◽  
Organic Clay ◽  
Poly Propylene

This work is mainly concentrated on the preparation and characterization of poly(propylene oxide) (PPO)/organic clay nanocomposites. The effects of the nature of organoclays and the method of preparation have been elucidated to evaluate their morphological, structural and thermal properties. These nanocomposites were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, thermal analysis (differential scanning calorimetry) and thermogravimetric analysis (TGA). This study involved the use of an Algerian clay called ‘maghnite’ which was modified by an incorporation method using different concentrations of the surfactant cetyltrimethylammonium bromide (CTAB). Propylene oxide (PO) was polymerized in the presence of ethylene glycol and various proportions of organic clay ranging from 1%, 5% and 10% by weight. The structural study by XRD showed, at different loading rates of maghnite and PO in the preparation of PPO/maghnite nanocomposites, different morphologies: intercalated/exfoliated blend and intercalated/agglomerated. TGA showed that the intercalation of PPO at the montmorillonite (MMT)-CTA interface would be more advantageous since the required amount of 5% organic clay (by weight) ensures high thermal stability of the nanocomposites, and the glass transition temperature ( T g) of PPO/MMT nanocomposites is higher than that of PPO since this increase is due to the introduction of clay into the matrix which makes the nanocomposite more rigid.

The Preparation and Characterization of ZnO/Graphene Nanocomposites

2014 ◽  
Vol 597 ◽  
pp. 21-27 ◽  
Author(s):  
Ze Peng Wang ◽  
Gui Long Wu ◽  
Yan He
Keyword(s):  
Electron Microscopy ◽  
High Surface ◽  
Single Layer ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Graphene Nanocomposites ◽  
X Ray ◽  
Transmission Electron ◽  
Zno Crystal

Graphene-based composites now has been payed more and more attention to because it can make up many shortcomings of the pure single-layer graphene.In many papers ,there are one same phenomenon said that graphene can not be well dispersed in matrix since it’s high specific surface area and high surface energy.In this work,we reported the preparation of ZnO/graphene nanocomposites through the way of situ-reaction in the surface of graphite oxide.Then,the nanocomposites were characterized by X-ray diffraction (XRD), Fourier Transform-Infared spectroscopy (FTIR),transmission electron microscopy (TEM), and thermogravimetry (TG). The results indicated that the graphene oxide had been reduced by hydrazine hydrate and the ZnO crystal attached to the surface of graphene well.The ZnO/graphene nanocomposites can be expected to be dispersed in some kinds of rubber to improve their electric and thermal conductivities in the following experiments.

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

Hydrothermal Synthesis and Characterization of BiFeO3 Polyhedral Crystallites

2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.

Microstructure Characterization of Metal Mixed Oxides

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4025-4030 ◽  
Author(s):  
T. Kryshtab ◽  
H. A. Calderon ◽  
A. Kryvko
Keyword(s):  
Mixed Oxides ◽  
Profile Analysis ◽  
Atomic Resolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Reconstruction Procedure ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Co Precipitation

ABSTRACTThe microstructure of Ni-Mg-Al mixed oxides obtained by thermal decomposition of hydrotalcite-like compounds synthesized by a co-precipitation method has been studied by using X-ray diffraction (XRD) and atomic resolution transmission electron microscopy (TEM). XRD patterns revealed the formation of NixMg1-xO (x=0÷1), α-Al2O3 and traces of MgAl2O4 and NiAl2O4 phases. The peaks profile analysis indicated a small grain size, microdeformations and partial overlapping of peaks due to phases with different, but similar interplanar spacings. The microdeformations point out the presence of dislocations and the peaks shift associated with the presence of excess vacancies. The use of atomic resolution TEM made it possible to identify the phases, directly observe dislocations and demonstrate the vacancies excess. Atomic resolution TEM is achieved by applying an Exit Wave Reconstruction procedure with 40 low dose images taken at different defocus. The current results suggest that vacancies of metals are predominant in MgO (NiO) crystals and that vacancies of Oxygen are predominant in Al2O3 crystals.

scholarly journals Synthesis and Characterization of K-Ta Mixed Oxides for Hydrogen Generation in Photocatalysis

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Beata Zielińska ◽  
Ewa Mijowska ◽  
Ryszard J. Kalenczuk
Keyword(s):  
Diffuse Reflectance ◽  
Hydrogen Generation ◽  
Mixed Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Photocatalytic Hydrogen Generation ◽  
Irregular Structure ◽  
Transmission Electron

K-Ta mixed oxides photocatalysts have been prepared by impregnation followed by calcination. The influence of the reaction temperature (450°C–900°C) on the phase formation, crystal morphology, and photocatalytic activity in hydrogen generation of the produced materials was investigated. The detailed analysis has revealed that all products exhibit high crystallinity and irregular structure. Moreover, two different crystal structures of potassium tantalates such as KTaO3and K2Ta4O11were obtained. It was also found that the sample composed of KTaO3and traces of unreacted Ta2O5(annealed at 600°C) exhibits the highest activity in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were examined by X-ray diffraction (XRD) and diffuse reflectance (DR) UV-vis and resonance Raman spectroscopic methods, respectively. Morphology and chemical composition of the produced samples were studied using a high-resolution transmission electron microscope (HR-TEM) and an energy dispersive X-ray spectrometer (EDX) as its mode.

scholarly journals Preparation and Characterization of Polyhydroxybutyrate/Polycaprolactone Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Cha Ping Liau ◽  
Mansor Bin Ahmad ◽  
Kamyar Shameli ◽  
Wan Md Zin Wan Yunus ◽  
Nor Azowa Ibrahim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Basal Spacing ◽  
Cooh Group ◽  
Physical Interaction ◽  
X Ray Diffraction ◽  
Ion Exchange Reaction ◽  
Transmission Electron ◽  
Matrix Enhancement ◽  
Double Hydroxide

Polyhydroxybutyrate (PHB)/polycaprolactone (PCL)/stearate Mg-Al layered double hydroxide (LDH) nanocomposites were prepared via solution casting intercalation method. Coprecipitation method was used to prepare the anionic clay Mg-Al LDH from nitrate salt solution. Modification of nitrate anions by stearate anions between the LDH layers via ion exchange reaction. FTIR spectra showed the presence of carboxylic acid (COOH) group which indicates that stearate anions were successfully intercalated into the Mg-Al LDH. The formation of nanocomposites only involves physical interaction as there are no new functional groups or new bonding formed. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the mixtures of nanocomposites are intercalated and exfoliated types. XRD results showed increasing of basal spacing from 8.66 to 32.97 Å in modified stearate Mg-Al LDH, and TEM results revealed that the stearate Mg-Al LDH layers are homogeneously distributed in the PHB/PCL polymer blends matrix. Enhancement in 300% elongation at break and 66% tensile strength in the presence of 1.0 wt % of the stearate Mg-Al LDH as compare with PHB/PCL blends. Scanning electron microscopy (SEM) proved that clay improves compatibility between polymer matrix and the best ratio 80PHB/20PCL/1stearate Mg-Al LDH surface is well dispersed and stretched before it breaks.

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