The Mechanism of the Decomposition of Nitrous Oxide on Zinc Oxide as Catalyst

Abstract

For the decomposition of nitrous oxide on metals and oxides, a tentative mechanism is indicated which involves quasi-free electrons as reactants and adsorbed oxygen ions as intermediate product. This mechanism is in accordance with experimental facts such as retardation by oxygen, a fractional order of the reaction with respect to nitrous oxide in the case of indium oxide as catalyst, and the decrease of the electrical conductivity of zinc oxide due to the presence of nitrous oxide. A mixture of zinc oxide and gallium oxide, however, has about the same catalytic activity as pure zinc oxide, although the electrical conductivity of the mixed catalyst is about fifty times greater than that of pure zinc oxide. This finding can be accounted for by the assumption that the reaction between nitrous oxide and electrons of the catalyst takes place in the vicinity of an adsorbed zinc ion or an anion vacancy.