Atomic Scale Observations of the Chemistry at the Metal–Oxide Interface in Heterogeneous Catalysts

2002 ◽  
Vol 205 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R.F. Klie ◽  
M.M. Disko ◽  
N.D. Browning
Keyword(s):  
Metal Oxide ◽  
Heterogeneous Catalysts ◽  
Atomic Scale ◽  
Oxide Interface

scholarly journals Atomic Scale Characterization of the Metal-Oxide Interface in Catalysts

2003 ◽  
Vol 9 (S02) ◽  
pp. 288-289
Author(s):  
H. Iddir ◽  
N. D. Browning
Keyword(s):  
Metal Oxide ◽  
Atomic Scale ◽  
Oxide Interface ◽  
Scale Characterization

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.

Electron holography of catalysts

1995 ◽  
Vol 53 ◽  
pp. 416-417
Author(s):  
A. K. Datye ◽  
D. S. Kalakkad ◽  
L. F. Allard ◽  
E. Völkl
Keyword(s):  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Scale ◽  
Nano Particles ◽  
Phase Image ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Phase Information ◽  
Particle Structure

The active phase in heterogeneous catalysts consists of nanometer-sized metal or oxide particles dispersed within the tortuous pore structure of a high surface area matrix. Such catalysts are extensively used for controlling emissions from automobile exhausts or in industrial processes such as the refining of crude oil to produce gasoline. The morphology of these nano-particles is of great interest to catalytic chemists since it affects the activity and selectivity for a class of reactions known as structure-sensitive reactions. In this paper, we describe some of the challenges in the study of heterogeneous catalysts, and provide examples of how electron holography can help in extracting details of particle structure and morphology on an atomic scale.Conventional high-resolution TEM imaging methods permit the image intensity to be recorded, but the phase information in the complex image wave is lost. However, it is the phase information which is sensitive at the atomic scale to changes in specimen thickness and composition, and thus analysis of the phase image can yield important information on morphological details at the nanometer level.

Surface to bulk charge transfer at an alkali metal/metal oxide interface

2003 ◽  
Vol 547 (1-2) ◽  
pp. L859-L864 ◽  
Author(s):  
R Lindsay ◽  
E Michelangeli ◽  
B.G Daniels ◽  
M Polcik ◽  
A Verdini ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Alkali Metal ◽  
Metal Oxide ◽  
Oxide Interface ◽  
Metal Metal ◽  
Bulk Charge

High temperature behavior of the metal/oxide interface of ferritic stainless steels

2012 ◽  
Vol 59 ◽  
pp. 148-156 ◽  
Author(s):  
Jérôme Issartel ◽  
Sébastien Martoia ◽  
Frédéric Charlot ◽  
Valérie Parry ◽  
Guillaume Parry ◽  
...  
Keyword(s):  
High Temperature ◽  
Metal Oxide ◽  
Stainless Steels ◽  
Temperature Behavior ◽  
Oxide Interface ◽  
Ferritic Stainless Steels ◽  
High Temperature Behavior

Fermi level pinning at the polySi/metal oxide interface

2004 ◽  
Author(s):  
C. Hobbs ◽  
L. Fonseca ◽  
V. Dhandapani ◽  
S. Samavedam ◽  
B. Taylor ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Fermi Level ◽  
Oxide Interface ◽  
Fermi Level Pinning

KINETICS OF THIN OXIDE FILM GROWTH ON METAL CRYSTALS

2000 ◽  
Vol 07 (01n02) ◽  
pp. 135-139 ◽  
Author(s):  
V. P. ZHDANOV ◽  
P. R. NORTON
Keyword(s):  
Oxide Film ◽  
Metal Oxide ◽  
Metal Ions ◽  
Film Growth ◽  
Phase Interface ◽  
Oxide Interface ◽  
Thin Oxide Film ◽  
Thin Oxide Films ◽  
Thin Oxide ◽  
Kinetics Of

A seminal model describing the kinetics of growth of thin oxide films on metal crystals was proposed by Cabrera and Mott (CM). The model is based on the assumption that the growth is limited by the field-facilitated activated jumps of metal ions located in steps on the metal–oxide interface. We generalize the CM model by (i) exploring the interplay of jumps of metal ions from the step and terrace sites at the metal–oxide interface, and (ii) scrutinizing the processes at the oxide–gas-phase interface. The former factor is found to change the physical meaning of the parameters in the CM growth law. The latter factor results in modification of the growth law. In particular, the oxidation kinetics becomes dependent on the O2 pressure. More specifically, the oxidation rate is predicted to increase with increasing pressure. This effect is, however, rather weak and becomes progressively weaker with increasing oxide film thickness.

Direct dehydrogenation of isobutane to isobutene over Zn-doped ZrO2 metal oxide heterogeneous catalysts

2018 ◽  
Vol 8 (19) ◽  
pp. 4916-4924 ◽  
Author(s):  
Yang Liu ◽  
Chengjie Xia ◽  
Qi Wang ◽  
Lei Zhang ◽  
Ao Huang ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Heterogeneous Catalysts ◽  
First Time

A series of unconventional nano-sized Zn-doped ZnZrO-x catalysts are applied for the first time to the direct dehydrogenation of isobutane to isobutene.

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