Simultaneous removal of soot and NOx with Ru-Ir/TiO2 catalyst under oxygen-rich condition

Abstract A series of Ru-Ir bimetallic catalysts with different mass ratios (Ru-Ir/TiO 2 , Ru:Ir = 9:1, 7:3, 5:5, 3:7, 1:9) were prepared by iso -volumetric impregnation method. The activities of the catalysts for simultaneous removal of soot and NO x were investigated by Temperature Programmed Surface Reaction (TPSR) technique, and the properties of the catalysts were characterized by various analysis techniques, such as XPS, XRD, TEM, H 2 -TPR, H 2 -TPD and nitrogen adsorption. The results indicated that Ru-Ir/TiO 2 bimetallic catalysts had better activity for simultaneous removal of soot and NO x than Ru/TiO 2 or Ir/TiO 2 . When the mass ratio of Ru:Ir was 9:1, the catalyst showed the best catalytic activity. The peak temperature of soot oxidation was 437 °C and the highest conversion efficiency of NO x was 42.6%. On the basis of the characterization of the catalysts, the relationship between the catalytic activity of Ru-Ir/TiO 2 and the synergetic roles of Ru and Ir was discussed.