CATALYTIC DECOMPOSITION OF DINITROGEN OXIDE OVER PEROVSKITE-RELATED MIXED OXIDES

The catalytic decomposition of dinitrogen oxide (N2O) was carried out over La2-xSrxCuO4 (x=0-1), LaMO(3) (M=Cr, Mn, Fe, Co, and Ni) and La(2 )MO(4) (M=Co, Ni, and Cu) mixed oxides with perovskite and perovskite- related structure. The reaction rate at the steady state was first-ord er in the partial pressure of N2O, with reversible inhibition of oxyge n. The initial rate was enhanced by pretreatment in helium at 1073 K, but decreased gradually due to irreversible inhibition of oxygen forme d by the reaction, while the rate increased with time when the catalys t was pretreated in oxygen. A good correlation between the catalytic a ctivity and the average oxidation number of copper (AON) was observed for La2-xSrxCuO4 and was explained by a Cu2+/Cu3+ redox mechanism. The catalytic activity for a series of LaMO(3) and La(2)MO(4) showed a on e peak pattern with Co at the peak. These trends in catalytic activity are similar in general to those for NO decomposition.