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 Co_xMg_1–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.