Consideration on the reaction mechanism of thallium oxide as a combustion catalyst of PM2.5

Seven types of oxide ion conductive ceramics (ZrO2)0.92(Y2O3)0.08, (CeO2)0.8(Gd2O3)0.2, La2Zr2O7, (Bi2O3)0.75(Y2O3)0.25, (ZrO2)0.90(Sc2O3)0.10, La9.7Si6O26.55, and La0.8Sr0.2Ga0.8Mg0.115Co0.085O3 were composited with Tl2O3, which has excellent carbon combustion characteristics, and their effects on carbon combustion characteristics were investigated. Although no improvement in the carbon combustion characteristics with Tl2O3 only was observed due to the composite with oxide ion conductive ceramics, the carbon combustion characteristics with Tl2O3 only were maintained at x wt% ? Tl2O3 + (Bi2O3)0.75(Y2O3)0.25 (x = 5, 10, 20). A mechanism other than ionic conduction was suggested for the carbon combustion characteristics of the Tl2O3 + oxide ion conductive ceramics composite.