Three-dimensionally ordered macroporous K0.5MnCeOx/SiO2 catalysts: facile preparation and worthwhile catalytic performances for soot combustion

Abstract

A series of novel and cheap catalysts were designed and successfully synthesized by a simple method. In these novel catalysts, three-dimensionally ordered macroporous (3DOM) SiO₂ is used as the support and two types of nanoparticles (Mn-rich and Ce-rich) with diameters in the range of 20–25 nm and 1.5–5 nm, respectively, were well dispersed and supported on the skeleton of 3DOM SiO₂. 3DOM K_0.5MnCeO_x/SiO₂ catalysts show superior catalytic performance for diesel soot oxidation, which can be attributed to the macroporous effect of the 3DOM structure, nano-effect of the active component, and synergetic effect among K, Mn, and Ce. Among the as-prepared catalysts, 3DOM K_0.5MnCeO_x/SiO₂-40 shows the highest catalytic activity, i.e., T₅₀ and T₉₀ values of 315 and 348 °C, respectively. This activity is one of the best results reported so far under the condition of loose contact between the soot particles and the catalyst. Due to facile synthesis, low cost, high catalytic activity, and high stability for diesel soot combustion, the as-prepared catalysts have promising practical applications in dealing with the exhaust of diesel engines.