Acid/base and surface features of pure phase magnesia powders

This paper reports data concerning the bulk and surface features of magnesi a powders prepared by calcination of different precursor salts at increasin g temperatures (873-1253 K). The bulk characterization of the oxides has be en obtained by X-ray diffraction, while the surface features have been inve stigated by means of N-2, adsorption at subcritical temperatures and X-ray photoelectron spectroscopy. The acid/base features have been analysed by ad sorption and strip titration of dye indicators with known pK(b) values, in benzene. The powders appear to be composed of pure periclase, with a degree of cryst allinity which is influenced by the nature of the precursor salt. The speci fic surface area and surface acid/base features of the samples are strongly dependent on both the nature of the precursor and the temperature of calci nation. On the other hand, XPS data seem to be totally independent of the p reparation route of the oxides, and acquire a general valence. (C) 1998 Els evier Science B.V. All rights reserved.