Characterization and hydrodesulfurization activity of CoMo catalysts supported on sol–gel prepared Al2O3

Activities in thiophene hydrodesulfurization were increased by a factor three when using aluminas, as support for CoMo catalysts, prepared using an optimized sol–gel method.

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Dibenzothiophene Hydrodesulfurization Activity of MoS2Supported in Sol–Gel ZrO2–TiO2Mixed Oxides

Petroleum Science and Technology ◽

10.1081/lft-120028525 ◽

2004 ◽

Vol 22 (1-2) ◽

pp. 87-101 ◽

Cited By ~ 5

Author(s):

María C. Barrera ◽

José Escobar ◽

Celia Marín ◽

Margarita Viniegra ◽

José A. De Los Reyes ◽

...

Keyword(s):

Sol Gel ◽

Hydrodesulfurization Activity

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Hydrodesulfurization Activity of CoMo Catalysts Supported on Stabilized TiO2

Energy & Fuels ◽

10.1021/ef020144u ◽

2003 ◽

Vol 17 (1) ◽

pp. 81-86 ◽

Cited By ~ 27

Author(s):

P. Schacht ◽

G. Hernández ◽

L. Cedeño ◽

J. H. Mendoza ◽

S. Ramírez ◽

...

Keyword(s):

Como Catalysts ◽

Hydrodesulfurization Activity

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TEM visualization of surface replicated acid and base catalyzed sol-gel glasses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014381x ◽

1986 ◽

Vol 44 ◽

pp. 448-449

Author(s):

George C. Ruben ◽

Merrill W. Shafer

Keyword(s):

Elevated Temperatures ◽

Sol Gel ◽

Basic Medium ◽

Glass Transition Point ◽

Structural Space ◽

Acid And Base ◽

Organometallic Precursors ◽

New Processing ◽

Gel Glasses ◽

Physical Phenomena

Traditionally ceramics have been shaped from powders and densified at temperatures close to their liquid point. New processing methods using various types of sols, gels, and organometallic precursors at low temperature which enable densificatlon at elevated temperatures well below their liquidus, hold the promise of producing ceramics and glasses of controlled and reproducible properties that are highly reliable for electronic, structural, space or medical applications. Ultrastructure processing of silicon alkoxides in acid medium and mixtures of Ludox HS-40 (120Å spheres from DuPont) and Kasil (38% K2O &62% SiO2) in basic medium have been aimed at producing materials with a range of well defined pore sizes (∼20-400Å) to study physical phenomena and materials behavior in well characterized confined geometries. We have studied Pt/C surface replicas of some of these porous sol-gels prepared at temperatures below their glass transition point.

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Electron microscopy studies of PZT ferroelectric film capacitor structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131450 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1364-1365

Author(s):

V. Kaushik ◽

P. Maniar ◽

J. Olowolafe ◽

R. Jones ◽

A. Campbell ◽

...

Keyword(s):

Electric Fields ◽

Sol Gel ◽

Ferroelectric Material ◽

Dielectric Constants ◽

Dielectric Films ◽

Lead Zirconium Titanate ◽

Si Substrate ◽

Film Capacitor ◽

Pzt Films ◽

High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

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The crystallization of thin-film ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122095 ◽

1992 ◽

Vol 50 (1) ◽

pp. 338-339

Author(s):

J.M. Schwartz ◽

L.F. Francis ◽

L.D. Schmidt ◽

P.S. Schabes-Retchkiman

Keyword(s):

Thin Films ◽

Grain Size ◽

Sol Gel ◽

Processing Route ◽

Small Areas ◽

Ceramic Thin Films ◽

Complex Shapes ◽

Sol Gel Process ◽

Ceramic Precursors ◽

Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

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The use of high-resolution FESEM to study solid-state phase transformations and reactions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172875 ◽

1994 ◽

Vol 52 ◽

pp. 1028-1029

Author(s):

P. G. Kotula ◽

D. D. Erickson ◽

C. B. Carter

Keyword(s):

Solid State ◽

High Resolution ◽

Phase Transformations ◽

High Efficiency ◽

Sol Gel ◽

Quantitative Information ◽

Solid State Reactions ◽

Critical Dimensions ◽

Backscattered Electrons ◽

Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

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Phase separation in sol gel-derived ceramic films of silica-zirconia, alumina-zirconia, and titania-zirconia system

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170967 ◽

1994 ◽

Vol 52 ◽

pp. 646-647

Author(s):

J. Tong ◽

L. Eyring

Keyword(s):

Fracture Toughness ◽

Phase Separation ◽

Sol Gel ◽

Great Influence ◽

High Strength ◽

Chemical Durability ◽

Separation Method ◽

Toughening Mechanism ◽

Ceramic Films ◽

Zirconia Toughened Alumina

There is increasing interest in composites containing zirconia because of their high strength, fracture toughness, and its great influence on the chemical durability in glass. For the zirconia-silica system, monolithic glasses, fibers and coatings have been obtained. There is currently a great interest in designing zirconia-toughened alumina including exploration of the processing methods and the toughening mechanism.The possibility of forming nanocrystal composites by a phase separation method has been investigated in three systems: zirconia-alumina, zirconia-silica and zirconia-titania using HREM. The morphological observations initially suggest that the formation of nanocrystal composites by a phase separation method is possible in the zirconia-alumina and zirconia-silica systems, but impossible in the zirconia-titania system. The separation-produced grain size in silica-zirconia system is around 5 nm and is more uniform than that in the alumina-zirconia system in which the sizes of the small polyhedron grains are around 10 nm. In the titania-zirconia system, there is no obvious separation as was observed in die alumina-zirconia and silica-zirconia system.

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