Activity of cobalt ions dispersed in magnesium oxide for the decomposition of nitrous oxide

Abstract

Abstract The catalytic decomposition of N 2 O has been studied over CoOMgO solid solutions (cobalt content from 0.05 to 50 atoms/100 Mg atoms), and over pure CoO. It has been shown that the activity per cobalt ion increases with dilution, and the apparent activation energy ranges from 17 kcal/mole on the most dilute solid solution to 29 kcal/mole on the most concentrated one and on pure CoO. Oxygen adsorption measurements taken during N 2 O decomposition or obtained directly from molecular oxygen suggest the existence of at least two forms of adsorbed oxygen. Higher oxygen coverages are achieved when N 2 O is decomposed: the result is discussed in terms of ionic interaction. The role of the matrix in oxygen desorption is examined: peroxy-ion formation is suggested as a possible mechanism. A comparison of the strength of the TO ads bonds on CoOMgO and NiOMgO solid solutions (T = Co, Ni) is presented and discussed in terms of electronic configuration.