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The 0.5 wt% Pd-CeMnO was prepared by ultrasonic intervention combination of Sol-Gel and PVA-protected N bubbling NaBH reduction impregnation method, then it was used for the catalytic oxidation of benzene vapour at low temperatures. By analyzing the removal and mineralization rate at different temperatures, it was found that 50% of benzene was degraded in 145 °C, then 90% of benzene was degraded in 186 °C, 100% of mineralization rate was 220 °C. After ultrasonic treatment, 64% removal rate and 46% mineralization rate could be increased, it proved that ultrasonic treatment can improve the performance of catalyst significantly. According to XRD spectrum, ultrasonic intervention helped to stabilize the crystalline structure of perovskite. Further, SEM pictures intuitively proved that ultrasonic treatment contributes to the formation of surface pore structure of catalyst. Moreover, diagram of H-TPR indicates that ultrasonic intervention makes the catalyst have more cryogenic activity sites for strong low temperature catalytic activities. All these reasons are assumed to be the factors that lead to superior performance of the catalyst.

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A series of Ir-based catalysts were prepared by ultrasonicassisted equal-volume impregnation to evaluate the catalytic performance of selective catalytic reduction of NOx by CO (CO-SCR) with excess O 2 in simulated flue gas. We investigated the effects of different carrier, Ir loading, and composite carrier ratio (W/Si) on the CO-SCR activities. The results showed that WO 3 and SiO 2 were effective carriers for the CO-SCR reaction under oxygen-rich conditions. Results of XRD and H 2 -TPR studies indicated that metal Ir strongly interacted with carrier WO 3 and SiO 2 , respectively, which improved the surface dispersion of active component Ir species and was conducive to the removal of NOx and CO. When W/Si molar ratio was 1/9 and Ir loading was 2 wt%, the Ir/WO 3 -SiO 2 catalyst reached 49 % NOx conversion and 76 % CO conversion at 225°C, while NO 2 yield was also only 5 ppm. The effects of O 2 , SO 2 , and H 2 O on the structure of Ir/WO 3 -SiO 2 were analyzed by XRD and XPS characterization methods. It was found that O 2 could oxidize Ir species to IrO 2 , thereby inhibiting NOx reduction. A low concentration of SO 2 can weaken the process of Ir oxidation, promote NOx reduction, and improve catalytic activity. H 2 O can reduce the NOx conversion rate and inhibit the CO-SCR reaction, but the inhibition effect is reversible.