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

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)(2)O-3.03 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)(2)O-3.03 catalyst exhibited the highest NO decomposition activity among the samples prepared; NO conversion to N-2 reached 90% at 1173 K in the absence of O-2 (NO/He atmosphere), and a relatively high conversion ratio was observed even in the presence of O-2, 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.