The ultrastructure of carbons, catalytically active graphitic compounds and zeolitic catalysts

Abstract

The value of high-resolution electron microscopy as a technique in coal science and technology is illustrated by reference to the study of the onset, on heating, of the crystallinity of relatively unstructured coals and carbonaceous solids; by the detection of changes, upon use, that occur in hydrodesulphurization catalysts; and by the direct imaging of structural features in ( a ) metal catalysts supported on graphitic carbons and ( b ) graphite intercalates of the kind known to be potentially useful in Fischer-Tropsch and related syntheses, which are commercially viable in the conversion of coal to petrols and chemicals. The technique is also capable of imaging directly the structure of a range of zeolites, including the A, X and Y types, and the ZSM-5 zeolitic catalysts, which figure eminently in the conversion of methanol to petrol. The advantages of high-resolution microscopy, compared with X-ray based methods for the problems peculiar to coal science, are stressed.