Study by electron microscopy and electron diffraction of formation of nickel epitaxially grown catalysts

Abstract

In order to study the influence of the crystallographic arrangement at the surface of a metal-supported catalyst on its catalytic properties, catalysts have been prepared with well faceted nickel crystallites presenting particular faces at their surface. Catalysts were obtained by reduction by hydrogen of nickel antigorite evacuated at different temperatures. The morphology and structure of nickel antigorite, the parent of the catalyst, has been determined by electron microscopy and electron diffraction at different temperatures. Rolled or flat sheets were observed. The texture of the catalysts obtained after reduction was determined. The crystallites of nickel are hexagonal platelets with either their (111) or their (110) plane parallel to the sheet support, depending on the conditions of preparation and reduction. Study of the orientations of (111) type or (110) type was done.