Stacking disorder in silicon carbide supported cobalt crystallites: an X-ray diffraction, electron diffraction and high resolution electron microscopy study

2016 ◽  
Vol 18 (43) ◽  
pp. 30183-30188 ◽  
Author(s):  
H. E. du Plessis ◽  
J. P. R. de Villiers ◽  
A. Tuling ◽  
E. J. Olivier
Keyword(s):  
Electron Microscopy ◽  
Supported Catalyst ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
X Ray ◽  
Resolution Electron ◽  
Stacking Disorder

Supported cobalt Fischer–Tropsch catalysts are characteristically nanoparticulate and the reduced SiC supported catalyst was found to contain both HCP and FCC polymorphs.

High‐resolution electron microscopy study of x‐ray multilayer structures

1987 ◽  
Vol 61 (4) ◽  
pp. 1422-1428 ◽  
Author(s):  
Amanda K. Petford‐Long ◽  
Mary Beth Stearns ◽  
C.‐H. Chang ◽  
S. R. Nutt ◽  
D. G. Stearns ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Multilayer Structures ◽  
X Ray ◽  
Resolution Electron

Gallium ZSM-5 type zeolites: A catalytical and structural electron microscopy study

1988 ◽  
Vol 46 ◽  
pp. 950-951
Author(s):  
Dwight R. Acosta ◽  
Isaac Schifter ◽  
José L. Contreras
Keyword(s):  
Electron Microscopy ◽  
Structural Characteristics ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
X Ray Diffraction ◽  
Modified Method ◽  
Selected Area Electron Diffraction ◽  
Resolution Electron ◽  
Cage Size

Synthesis of stereo selective zeolites using Gallium as partial or total substitute instead of aluminum, may lead to obtention of a novel class of zeo lites with modification of channel apertures, cage size and total acidity. Reaction velocity and selectivity for isomerization and cracking processes, for instance, are influenced by acid force of protonic sites, which may be selective or active for particular catalytic reactions.Zeolites Z-683 and Z-691 with a 50% and 100% of A1 atoms substituted respectively, were synthesized using a modified method for ZSM-5 zeolite crystallization as described in the literature. The samples obtained were studied using ammonia (NH3) thermodesorption techniques. X-ray diffraction, high resolution electron microscopy, selected area electron diffraction and optical diffractometry methods were used in order to determine structural characteristics of zeolites above mentioned.Figure 1 shows the results of NH3 thermodesortion studies for three zeolites: Z-601 (ZSM-5), Z-683 (50% A1 - 50% Ga) and Z-691 (100% Ga).

A high resolution and Analytical Electron Microscopy study of novel solid state hydrodesulfurization catalysts

1989 ◽  
Vol 47 ◽  
pp. 264-265
Author(s):  
J. Lindner ◽  
A. Sachdev ◽  
M.A. Villa-Garcia ◽  
J. Schwank
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
High Resolution ◽  
Analytical Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
X Ray Diffraction ◽  
Hydrodesulfurization Catalysts ◽  
Resolution Electron

The removal of sulfur from petroleum feedstocks is of great importance to the oil industry. The process, known as hydrodesulfurization (HDS), is typically catalyzed by Group VIB metal oxides. The workhorse of the industry today is an alumina supported CoO-MoO3 catalyst. Recently, several models have been proposed for the active site responsible for HDS activity, but despite extensive research efforts there is still no clear relationship between structure and activity. We have prepared promoted and non-stoichiometric catalyst samples via a novel solid state synthesis route. These catalysts are not only quite active in the HDS of thiophene, but are also more thermally stable and consequently easier to characterize than the standard HDS materials prepared by wet chemistry methods. Most studies on HDS catalysts rely on bulk techniques for characterization analysis, however, these do not provide any information at the microscopic level where catalysis occurs. For that reason we have used analytical and high resolution electron microscopy to obtain information at the atomic level, coupled with bulk techniques such as x-ray diffraction and surface area measurements. The objective was to develop a link between the microstructure of our solid state catalysts and their HDS activity.

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