Advanced Electron Microscopy Characterization of Nanostructured Heterogeneous Catalysts

2004 ◽  
Vol 10 (1) ◽  
pp. 55-76 ◽  
Author(s):  
Jingyue Liu
Keyword(s):  
Electron Microscopy ◽  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Nanostructured Catalysts ◽  
Catalyst Characterization ◽  
Challenges And Opportunities ◽  
Recent Developments ◽  
Microscopy Characterization ◽  
Microscopy Techniques

Heterogeneous catalysis is one of the oldest nanosciences. Although model catalysts can be designed, synthesized, and, to a certain degree, characterized, industrial heterogeneous catalysts are often chemically and physically complex systems that have been developed through many years of catalytic art, technology, and science. The preparation of commercial catalysts is generally not well controlled and is often based on accumulated experiences. Catalyst characterization is thus critical to developing new catalysts with better activity, selectivity, and/or stability. Advanced electron microscopy, among many characterization techniques, can provide useful information for the fundamental understanding of heterogeneous catalysis and for guiding the development of industrial catalysts. In this article, we discuss the recent developments in applying advanced electron microscopy techniques to characterizing model and industrial heterogeneous catalysts. The importance of understanding the catalyst nanostructure and the challenges and opportunities of advanced electron microscopy in developing nanostructured catalysts are also discussed.

Recent Developments in Transmission Electron Microscopy Techniques to the Characterization of Cycled Li-Ion Electrode Materials

2019 ◽  
Vol 3 (27) ◽  
pp. 139-153 ◽  
Author(s):  
Loic Dupont ◽  
Lydia Laffont ◽  
Sylvie Grugeon ◽  
Stephane Laruelle ◽  
Vincent Bodenez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electrode Materials ◽  
Transmission Electron ◽  
Recent Developments ◽  
Li Ion ◽  
Microscopy Techniques

Electron Microscopy Characterization of Low-Temperature Growth Zn-doped TiO2 Nanowires

2009 ◽  
Vol 1178 ◽  
Author(s):  
Micah Eastman ◽  
Haiyan Li ◽  
Jun Jiao
Keyword(s):  
Electron Microscopy ◽  
Tio2 Nanowires ◽  
Doped Tio2 ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Microscopy Characterization ◽  
Microscopy Techniques ◽  
Constituent Elements ◽  
Electron Energy Loss

AbstractWe report the synthesis of Zn-doped TiO2 nanowires by a solution-based process. The synthesis takes place at 200°C in an alkali solution and results in both nanowire and nanoparticle precipitates. Several transmission electron microscopy techniques were used to characterize the resulting precipitates: diffraction patterns and high resolution phase contrast images provided identification of the crystalline phase of the material as well as insights into the resulting lattice parameters, energy dispersive x-ray spectroscopy allowed identification of constituent elements, and electron energy loss spectroscopy permitted quantification of relative concentrations of hydroxyl and lattice-type oxygen bonding. In addition, scanning electron microscope images provide overall perspective of the growth uniformity and morphology.

Crosslink Densities and Phase Morpholgies in Dynamically Vulcanized TPEs

1995 ◽  
Vol 68 (4) ◽  
pp. 573-584 ◽  
Author(s):  
Maria D. Ellul ◽  
Jaymini Patel ◽  
Andrew J. Tinker
Keyword(s):  
Electron Microscopy ◽  
Nmr Spectroscopy ◽  
Crosslink Density ◽  
Thermoplastic Elastomers ◽  
Network Visualization ◽  
Visualization Technique ◽  
Recent Developments ◽  
Microscopy Techniques ◽  
Crosslink Densities

Abstract Recent developments in characterization techniques have permitted estimation of the crosslink density attained in dynamically vulcanized thermoplastic elastomers. The range of techniques available for investigation of the phase morphology of this type of TPE has also increased. The characterization of experimental TPEs based on natural rubber/polypropylene and EPDM/polypropylene is reported here. A combination of several optical and electron microscopy techniques were employed. Crosslink densities estimated by swollen-state NMR spectroscopy are presented and are corroborated by estimates from a network visualization technique for TPEs.

Quantitative nano-characterization of heterogeneous catalysts

1995 ◽  
Vol 53 ◽  
pp. 398-399
Author(s):  
P.A. Crozier ◽  
M. Pan
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Dose ◽  
Imaging Techniques ◽  
Structural Features ◽  
Catalyst Characterization ◽  
New Developments ◽  
Double Phase ◽  
Phase Systems ◽  
Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

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