Sol-gel chemistry of transition metal oxides

http://xrm.phys.northwestern.edu/research/pdf_papers/2004/egerton_micron_2004.pdf

Radiation damage in the TEM and SEM.

Filamentous growth of carbon through benzene decomposition

Big is beautiful--"aromaticity" revisited from the viewpoint of macromolecular and supramolecular benzene chemistry.

Catalytic growth of carbon filaments

Carbon formation on iron and nickel foils by hydrocarbon pyrolysis—reactions at 700°C

THE existence of fibrous or whisker carbon has been reported in both synthetic studies of graphite1,2 and in naturally occurring graphite3. The synthetic studies involved decomposition of hydrocarbons over metals1 and decomposition of carbon monoxide over iron2 and, particularly in the second of these studies, the occurrence of metal catalyst within the fibre was observed. Furthermore, it has been established1 that the average orientation of the carbon crystallites is with their (0002) orientation parallel to the axis of the fibre. In this communication we describe the use of high resolution electron microscopy to establish the precise relationship between the orientation of the graphite planes and the catalyst particle within the fibre.

Structure of Fibrous Carbon

The resolution of electron microscopy may be extended by combining the phase information in microscope images with electron diffraction intensities. A general method for obtaining structural reconstructions at a resolution greater than that of the phase information is demonstrated for crystals of perchlorocoronene. By using entropy maximization methods combined with likelihood ranking, the resolution is extended from 0.32 nm in the microscope images to 0.1 nm in the reconstruction from phase and intensity data.

Electron microscopy at 1-Å resolution by entropy maximization and likelihood ranking

The micropore structure of disordered carbons determined by high resolution electron microscopy

The hydrolysis products of zirconyl chloride, produced by reflux of a 0.055 M solution, have been studied by high-resolution electron microscopy. Removal of samples of the solution at various stages of hydrolysis, together with examination of the solids obtained by rapid dehydration of these samples, has enabled structural units consistent in size with the tetrameric cation [Zr(OH) 2 4H 2 O] 4 8+ to be resolved in the electron microscope. These data indicated that there were species present in solution similar to those present in crystalline zirconyl chloride octahydrate. Later stages of the hydrolysis produced polymerization of these species until monoclinic ZrO 2 was obtained. A suggested mechanism relating these various structures was supported by pH measurements taken during the hydrolysis.

J.R. Fryer

Papers

Carbon formation on iron and nickel foils by hydrocarbon pyrolysis—reactions at 700°C

Structure of Fibrous Carbon

Electron microscopy at 1-Å resolution by entropy maximization and likelihood ranking

The micropore structure of disordered carbons determined by high resolution electron microscopy

An electron microscopic study of the hydrolysis products of zirconyl chloride