Structure and catalytic activity of CoxMg1–xAl2O4 spinel solid solutions. Part 2.—Decomposition of N2O

Abstract

The catalytic decomposition of N2O was studied on spinel catalysts of general formula CoxMg1–xAl2O4(x= 0 → 1). The bulk distribution of Co2+ ions is predominantly tetrahedral with a small fraction of Co2+ in octahedral symmetry. It is shown that the octahedral coordination of Co2+ allows a catalytic activity larger than that attributable to tetrahedral coordination. The results also indicate that the surface Co2+ distribution is different from that found in the bulk by X-rays.

The influence of the matrix on the activity is discussed in terms of surface—oxygen bond strength and a comparison is made with MgO- and ZnO- based catalysts.