Role of CeO2–ZrO2 in diesel soot oxidation and thermal stability of potassium catalyst

Potassium nitrate catalysts supported on different oxides (CeO2, Ce0.5Zr0.5O2 and ZrO2) were prepared for diesel soot combustion. The ageing treatment was performed at 800 °C for 24 h and the catalytic activity was evaluated by a temperature-programmed oxidation technique. The results demonstrated that, compared with CeO2 and ZrO2, Ce0.5Zr0.5O2 presented good redox properties, a high surface area and available potassium-holding capacity at an elevated temperature. For aged K/Ce0.5Zr0.5O2, the combustion temperature of soot particle was 359 °C under tight contact conditions and 455 °C under loose contact conditions. Thus, ceria–zirconia mixed oxides were considered as good candidate supports for diesel soot oxidation catalysis.