Study on oxidation activity of Ce–Mn–K composite oxides on diesel soot

As an effective method, diesel particulate filter (DPF) technology has a great contribution in reducing soot emissions from diesel engines. To achieve passive regeneration of DPF at low temperatures, K-doped Ce(0.5)Mn(0.5)O(2) catalysts were synthesized using sol–gel method. The effect of K-doped catalysts-K(z)–Ce(0.5)Mn(0.5)O(2)-on the oxidation of soot had been studied by thermogravimetric analysis, and the corresponding catalytic properties were evaluated based on X-ray diffraction (XRD), hydrogen temperature programmed reduction (H(2)-TPR), O(2) temperature programmed desorption (O(2)-TPD) Raman spectroscopy (Raman), Brunauer–Emmett–Teller (BET) and Fourier-Transform-Infrared (FTIR).The results showed that K doping facilitated the oxidation of diesel particulate matter, which was indicated by the entire mass loss curve shifting to lower temperatures. K(0.2)–Ce(0.5)Mn(0.5)O(2) showed the best performance among the series of K-doped catalysts. Compared with the findings for Ce(0.5)Mn(0.5)O(2), the ignition temperature of soot oxidation (T(i)) had been lowered by 28 ℃, and the maximum peak combustion temperature (T(m)) of the dry soot decreased by 61 °C. Furthermore, compared with the Ce(0.5)Mn(0.5)O(2)-catalyzed reaction, K doping led to a lower activation energy and significantly improved pre-exponential factor. The minimum reaction activation energy of 27.46 kJ/mol was exhibited by K(0.2)–Ce(0.5)Mn(0.5)O(2).