Post-Mortem investigation of Fischer Tropsch catalysts using cryo- transmission electron microscopy

2008 ◽  
pp. 249-250
Author(s):  
Dogan Ozkaya ◽  
Martin Lok ◽  
John Casci ◽  
Peter Ash
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Post Mortem ◽  
Fischer Tropsch ◽  
Transmission Electron

scholarly journals Optimization of ultrastructural preservation of human brain for transmission electron microscopy after long post-mortem intervals

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Mariella Sele ◽  
Stefan Wernitznig ◽  
Saška Lipovšek ◽  
Snježana Radulović ◽  
Johannes Haybaeck ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Human Brain ◽  
Post Mortem ◽  
Transmission Electron

From Nanoparticles to Process: An Aberration-Corrected TEM Study of Fischer-Tropsch Catalysts at Various Steps of the Process

2011 ◽  
Vol 324 ◽  
pp. 197-200 ◽  
Author(s):  
Nadi Braidy ◽  
Carmen Andrei ◽  
Jasmin Blanchard ◽  
Nicolas Abatzoglou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Amorphous Carbon ◽  
Spherical Aberration ◽  
Fischer Tropsch ◽  
Ft Synthesis ◽  
Transmission Electron ◽  
Treatment Step ◽  
Aberration Corrected

χThe nanostructure of Fischer-Tropsch (FT) Fe carbides are investigated using aberration-corrected high-resolution transmission electron microscopy (TEM). The plasma-generated Fe carbides are analyzed just after synthesis, following reduction via a H2 treatment step and once used as FT catalyst and deactivated. The as-produced nanoparticles (NPs) are seen to be abundantly covered with graphitic and amorphous carbon. Using the extended information limit from the spherical aberration-corrected TEM, the NPs could be indexed as a mixture of NPs in the θ-Fe3C and χ–Fe5C2 phases. The reduction treatment exposed the NPs by removing most of the carbonaceous speSubscript textcies while retaining the χ–Fe5C2. Fe-carbides NPs submitted to conditions typical to FT synthesis develop a Fe3O4 shell which eventually consumes the NPs up to a point where 3-4 nm residual carbide is left at the center of the particle. Subscript textVarious mechanisms explaining the formation of such a microstructure are discussed.

Analysis of the Promoter-Catalyst interaction between Mn and Rh by Transmission Electron Microscopy

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
B. Graham ◽  
R.F. Klie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Average Particle Size ◽  
Lattice Parameter ◽  
Average Particle ◽  
Fischer Tropsch ◽  
Transmission Electron ◽  
Three Samples ◽  
Promoter Interaction

In the hope of optimizing the Fischer-Tropsch mechanism to produce cleaner ethanol, the catalyst- promoter interaction between rhodium and manganese was examined by transmission electron microscopy. Three samples were analyzed on a carbon nanotube (CNT) substrate with 3 wt% rhodium (3%Rh/CNT), 1% manganese with 3 wt% rhodium (1%Mn/3% Rh/CNT), and 2% manganese with 3 wt% rhodium (2% Mn/3% Rh/CNT). The average particle size were found to be (1.9 ± 0.6) nm, (2.1 ± 0.5) nm, and (3.2 ± 0.6) nm, respectively. An increase in particle size indicates that the rhodium and manganese are interacting. The lattice parameter for rhodium were also determined to be (4.1 ± 0.1) Å, (4.2 ± 0.1) Å, and (3.8 ± 0.1) Å, respectively. The decrease in lattice parameter in the 2%Mn/3%Rh/CNT sample was most likely due to a change in the crystal structure of the rhodium particles as a result of the interaction between the manganese and rhodium.

A Preliminary Study of Thin Bird Disease

1981 ◽  
Vol 39 ◽  
pp. 602-603
Author(s):  
Ronald W. Davis ◽  
Samual Kenzy ◽  
Erik H. Stauber
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Weight Loss ◽  
Light Microscopy ◽  
Critical Point ◽  
Post Mortem ◽  
Post Mortem Examination ◽  
Transmission Electron ◽  
Half Strength ◽  
Preliminary Study

We have initiated a study of a disease that is usually fatal to domestic parakeets and canaries. We have called this syndrome “thin bird disease” for lack of a better name.Clinically, the disease is diagnosed after observing a bird that is thin, exhibits severe weight loss, lethargy, and ruffled feathers. Fecal smears of affected birds contain many very large, single-celled, rod-shaped bacteria measuring up to 1μm x 90μm.Post mortem examination of birds exhibiting external symptoms of the disease reveals an enlarged ventriculus (gizzard) that contains unmacerated seeds. A jelly-like mass is found in the ventriculus and pro-ventriculus of affected birds. This material contains bacteria morphologically identical to those found in fecal smears (Figs. 3, 4).Samples of ventriculus and pro-ventriculus from birds clinically diagnosed as diseased and normal were collected and processed for light microscopy, scanning and transmission electron microscopy. The specimens were fixed in half strength Karnovsky's fixative, post fixed in OsO4, and either embedded in plastic or critical point dried.

scholarly journals The effect of Mg location on Co-Mg-Ru/γ-Al 2 O 3 Fischer–Tropsch catalysts

2016 ◽  
Vol 374 (2061) ◽  
pp. 20150087 ◽  
Author(s):  
James R. Gallagher ◽  
Paul Boldrin ◽  
Gary B. Combes ◽  
Don Ozkaya ◽  
Dan I. Enache ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
High Resolution ◽  
Oxide Phase ◽  
Fischer Tropsch ◽  
Transmission Electron ◽  
Acid Washing ◽  
Higher Temperature

The effectiveness of Mg as a promoter of Co-Ru/γ-Al 2 O 3 Fischer–Tropsch catalysts depends on how and when the Mg is added. When the Mg is impregnated into the support before the Co and Ru addition, some Mg is incorporated into the support in the form of Mg x Al 2 O 3+ x if the material is calcined at 550°C or 800°C after the impregnation, while the remainder is present as amorphous MgO/MgCO 3 phases. After subsequent Co-Ru impregnation Mg x Co 3− x O 4 is formed which decomposes on reduction, leading to Co(0) particles intimately mixed with Mg, as shown by high-resolution transmission electron microscopy. The process of impregnating Co into an Mg-modified support results in dissolution of the amorphous Mg, and it is this Mg which is then incorporated into Mg x Co 3− x O 4 . Acid washing or higher temperature calcination after Mg impregnation can remove most of this amorphous Mg, resulting in lower values of x in Mg x Co 3− x O 4 . Catalytic testing of these materials reveals that Mg incorporation into the Co oxide phase is severely detrimental to the site-time yield, while Mg incorporation into the support may provide some enhancement of activity at high temperature.

Role of the Interfaces on the Activation of Slip Systems in The PST TiAl Alloy

1998 ◽  
Vol 552 ◽  
Author(s):  
Slim Zghal ◽  
Haruyuki Inui ◽  
Masaharu Yamaguchi ◽  
Alain Couret
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tial Alloy ◽  
Slip Systems ◽  
Post Mortem ◽  
Transmission Electron ◽  
In Situ Observations ◽  
Deformation Modes

ABSTRACTThe operative slip systems in the so-called PST alloy are determined by transmission electron microscopy. Both post-mortem analyses and in situ observations are presented. It is shown that glide of ordinary dislocations and twinning are the most easily deformation modes activated at yield. The role of the interfaces on the activation of these operative slip systems is then examined and discussed.

Studying Fischer–Tropsch catalysts using transmission electron microscopy and model systems of nanoparticles on planar supports

2011 ◽  
Vol 1 (5) ◽  
pp. 689 ◽  
Author(s):  
P. C. Thüne ◽  
C. J. Weststrate ◽  
P. Moodley ◽  
A. M. Saib ◽  
J. van de Loosdrecht ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Model Systems ◽  
Fischer Tropsch ◽  
Transmission Electron

The changes caused by activation and reaction conditions on the morphology of iron catalysts

1994 ◽  
Vol 52 ◽  
pp. 778-779
Author(s):  
D. S. Kalakkad ◽  
M. Shroff ◽  
A. K. Datye
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Deposition ◽  
Low Cost ◽  
Iron Catalysts ◽  
Synthetic Fuels ◽  
Fischer Tropsch ◽  
Reaction Conditions ◽  
Transmission Electron ◽  
Fe Catalysts

Iron is considered to be one of the most active/low cost catalysts for Fischer-Tropsch synthesis (FTS) used to produce higher order hydrocarbons and synthetic fuels from coal. One of the biggest obstacles faced by the industry in the use of iron is that of rapid deactivation and attrition. While it is generally accepted that deactivation occurs due to carbon deposition or “coking”, the actual steps involved in the formation and deposition of carbon have not yet been thoroughly understood. Also, the causes for attrition in these catalysts have not yet been established.Our present study involves use of transmission electron microscopy to find the effect of various pretreatment and reaction conditions on the microstructure of Fe catalysts and scanning electron microscopy to study the problem of attrition. The transmission electron microscopy was performed on a 200 kVJEOL JEM 2000FX microscope and the SEM was done using a Hitachi S800 microscope.

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