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-order in the partial pressure of N2O, with reversible inhibition of oxygen. The initial rate was enhanced by pretreatment in helium at 1073 K, but decreased gradually due to irreversible inhibition of oxygen formed by the reaction, while the rate increased with time when the catalyst was pretreated in oxygen. A good correlation between the catalytic activity 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 one peak pattern with Co at the peak. These trends in catalytic activity are similar in general to those for NO decomposition.