Catalytic properties, surface composition, and acidity of Ga-ZSM-5 catalysts for aromatization of lower paraffins

1991 ◽  
Vol 40 (12) ◽  
pp. 2373-2378
Author(s):  
D. P. Shevchenko ◽  
A. A. Dergachev ◽  
G. I. Zhuravlev ◽  
L. M. Kustov ◽  
O. P. Tkachenko ◽  
...  
Keyword(s):  
Surface Composition ◽  
Catalytic Properties

Catalytic Properties of ZrB2-Based Ultra-High Temperature Ceramics Based on the Wall Temperature Response Method

2013 ◽  
Vol 745-746 ◽  
pp. 636-641 ◽  
Author(s):  
Ning Li ◽  
Ping Hu ◽  
Xing Hong Zhang ◽  
Wen Bo Han
Keyword(s):  
High Temperature ◽  
Wall Temperature ◽  
Surface Composition ◽  
Catalytic Properties ◽  
Temperature Response ◽  
Ultra High Temperature Ceramics ◽  
Balance Principle ◽  
Sic Composites ◽  
Response Method ◽  
Ultra High Temperature

This paper presented the application of microwave-discharge plasma apparatus which was used to evaluate the catalytic properties of ZrB2-based ultra-high temperature ceramics in the simulated real service environment by the wall temperature response method based on the heat balance principle. The results showed that the material composition had a significant influence on the catalytic properties of ZrB2-based ultra-high temperature ceramics, and the catalytic activity of ZrB2-SiC composites with Cr addition had been increased significantly. The relationship between catalytic properties of ZrB2-based ultra-high temperature ceramics and surface composition was discussed in detail. The composition optimization was considered to be a very effective way to inhibit the recombination reactions of dissociated atoms on the surface of ultra-high temperature ceramics.

Relationship between the catalytic properties and surface composition of a polycrystalline Fe—Ni ribbon

1990 ◽  
Vol 58 (1) ◽  
pp. 219-225 ◽  
Author(s):  
P. Bussière ◽  
J.L. Duvault ◽  
M. Forissier ◽  
D. Foujols ◽  
C. Mirodatos ◽  
...  
Keyword(s):  
Surface Composition ◽  
Catalytic Properties

scholarly journals Tuning Catalytic Properties of Supported Bimetallic Pd/Ir Systems in the Hydrogenation of Cinnamaldehyde by Using the “Water-in-Oil” Microemulsion Method

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Tomasz Szumełda ◽  
Alicja Drelinkiewicz ◽  
Francesco Mauriello ◽  
Maria Grazia Musolino ◽  
Anna Dziedzicka ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Bimetallic Catalysts ◽  
Surface Composition ◽  
Catalytic Properties ◽  
Microemulsion Method ◽  
Monometallic Catalysts ◽  
Preparation Conditions ◽  
Supported Pd

Supported Pd/Ir bimetallic catalysts were synthesized by the “water-in-oil” microemulsion method at different precursor concentrations and characterized by XRD, XPS, SEM, TEM, and cyclic voltammetry. Depending on the preparation conditions, formation of bimetallic catalysts with different metal segregation and surface composition can be easily obtained, thus tuning the bimetallic structure of catalysts as well as their relative catalytic properties. Bimetallic Pd/Ir systems were efficiently tested in the hydrogenation of cinnamaldehyde showing a better performance than analogous monometallic catalysts.

Glassy Ni63.7Zr36.3 alloy: Surface composition and catalytic properties in hydrogenation of 1.3 butadiene

1987 ◽  
Vol 29 (1) ◽  
pp. 29-39 ◽  
Author(s):  
J.C. Bertolini ◽  
J. Brissot ◽  
T. Le Mogne ◽  
H. Montes ◽  
Y. Calvayrac ◽  
...  
Keyword(s):  
Surface Composition ◽  
Catalytic Properties ◽  
Alloy Surface

Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

1981 ◽  
Vol 39 ◽  
pp. 16-17
Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Probe Field ◽  
Preferential Sputtering ◽  
Argon Ion Bombardment ◽  
Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

Electron distribution change of small nickel particles encaged in X zeolite in presence of Ce3+ ions, related to their catalytic properties

1986 ◽  
Vol 83 ◽  
pp. 619-621 ◽  
Author(s):  
F. Vergand ◽  
B. Iraqi ◽  
C. Bonnelle ◽  
E. Ramaroson ◽  
M.F. Guilleux ◽  
...  
Keyword(s):  
Electron Distribution ◽  
Catalytic Properties ◽  
Distribution Change ◽  
Nickel Particles ◽  
X Zeolite

Countercation effects on surface and catalytic properties of 12-tungstophosphates

1992 ◽  
Vol 89 ◽  
pp. 681-693
Author(s):  
A Anwar ◽  
AA Abdel-Ghaffar
Keyword(s):  
Catalytic Properties
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