Direct Decomposition of NO into N2 and O2 on C-type Cubic Y2O3–ZrO2 and Y2O3–ZrO2–BaO

Abstract

Abstract Catalytic activities for direct NO decomposition were investigated on C-type cubic Y2O3–ZrO2 and Y2O3–ZrO2–BaO prepared by coprecipitation. Introduction of excess oxide anions in the Y2O3 lattice was achieved by partial substitution of the Y3+ sites with Zr4+, and high NO decomposition activity was obtained for the (Y0.97Zr0.03)2O3.03 catalyst. In addition, the catalytic activity was further enhanced by partial substitution of the Y3+ sites in the Y2O3–ZrO2 solid solution with Ba2+, and the (Y0.89Zr0.07Ba0.04)2O3.03 catalyst exhibited the highest NO decomposition activity among the samples prepared; NO conversion to N2 reached 90% at 1173 K in the absence of O2 (NO/He atmosphere), and a relatively high conversion ratio was observed even in the presence of O2, H2O, or CO2, compared with the activities of conventional direct NO decomposition catalysts. These results indicate that the C-type cubic Y2O3–ZrO2–BaO catalyst is a new potential candidate for direct NO decomposition.