Three-dimensionally ordered macroporous spinel-type MCr2O4 (M = Co, Ni, Zn, Mn) catalysts with highly enhanced catalytic performance for soot combustion

Three-dimensionally ordered macroporous (3DOM) spinel-type MCr2O4 (M = Co, Ni, Zn, Mn) catalysts were successfully prepared by a colloidal crystal template strategy and characterized by means of XRD, FE-SEM, BET, FT-IR, H-2-TPR and O-2-TPD. The 3DOM catalysts exhibited superior activity to their corresponding bulk counterparts, which were used as reference benchmarks in this study, due to the enlarged contact between the catalyst and the soot particle and improved mass transfer caused by the unique well-defined 3DOM structures. Meanwhile, the factors influencing the catalytic activity of the 3DOM catalysts in soot combustion were also optimized, such as metallic cations and feed compositions. Furthermore, the 3DOM catalysts displayed strong durability against structural collapse due to the robust 3DOM structure, demonstrating their promising potential in view of the practical working conditions of diesel engines.