Structure and Catalytic Activity of Iron Oxide and Magnesium Oxide Solid Solutions: Part 3- E.S.R. Characterization

Abstract

Magnesium oxide + iron oxide, fired both in air and in a reducing atmosphere, and magnesium oxide + iron oxide + lithium oxide (up to 1 % atomic Fe) were investigated by e.s.r. spectroscopy.

The effects of outgassing at various temperatures and of N2O decomposition on the e.s.r. spectra are discussed in terms of surface redox processes. The incipient formation of the spinel phase, MgeFe2O4, and its precipitation, at the highest outgassing temperatures adopted, were readily studied by the e.s.r. technique.

The hypotheses previously proposed on the modification of the catalyst solid state, occurring during N2O decomposition and/or in the vacuum treatment, are confirmed by the present study. Further details are also given.