The Effect of Synthesis Methods on Active Oxygen Species of MnOx-CuO in Soot Combustion

The activity of the catalyst is closely related to the synthesis method. Hereon, we prepared a series of XMn1Cu (X = 2, 4, 6, 8) catalysts by hydrolysis driven redox, co-precipitation and hydrothermal synthesis approaches, respectively. The effect of XMn1Cu synthesized by different strategies on soot combustion activity were compared. The results show that the catalysts fabricated by hydrolysis driven redox have excellent performance than the other two methods in soot removal, and the activity follows r-XMn1Cu > h-XMn1Cu > cop-XMn1Cu. The Mn/Cu = 4:1 is the optimal ratio of Cu-Mn composite oxide. Among the materials, the r-4Mn1Cu sample has the best catalytic activity due to the uniform distribution of Mn and Cu, high specific surface area, enhanced content of Mn4+, promoted concentration of lattice defects and oxygen vacancies, and T10, T50 and T90 are 303, 355 and 386 °C, respectively. The repeated experiments present that r-4Mn1Cu has high activity and stability in soot oxidation. Combined with experimental results and characterization, oxygen vacancies and reactive oxygen generation mechanism of XMn1Cu catalyst in soot combustion were further discussed.