Activity and Stability of Cu-Based Spinel-Type Complex Oxides for Diesel Soot Combustion

A series of Cu-based spinel-type complex oxides (CuB2O4, B=Fe, Mn, Co and Cr) was synthesized via sol-gel method for soot combustion. The soot combustion was accelerated in the presence of all prepared CuB2O4 catalysts compared to that without catalyst. The CuCo2O4 catalyst exhibited the best catalytic activity, with the soot combustion temperatures T-10, T-50 and T-90 of 480 degrees C, 539 degrees C and 569 degrees C, respectively. XRD patterns showed that the catalysts were mainly in spinel phase. The H-2-TPR, XPS and O-2-TPD characterizations revealed that the interactions between cobalt and copper led to higher content of the Cu+ species, better redox properties and abundant adsorbed oxygen species than the other three catalysts, which contributed to soot combustion. In addition, the catalytic activity of the CuCo2O4 catalysts on soot combustion were facilitated in the presence of NO, while water vapor inhibited the catalytic activity. Besides, the cycle tests clarified that CuCo2O4 catalyst exhibited good stability.