Mn-Cu/<italic>γ</italic>-Al₂O₃ Catalyst for NO<italic>_x</italic>-Assisted Soot Catalytic Combustion

The x% Mn-y% Cu/γ-Al2O3 catalysts were prepared by the impregnation method and deposition precipitation method. X-ray powder diffraction （XRD）， H2-temperature programmed （H2-TPR）， and X-ray photoelectron spectroscopy （XPS） characterized the structure of the catalysts. The activity of lattice oxygen and NO adsorption/oxidation properties of the catalysts were investigated by soot-TPR and NO-TPD. The catalytic performance of soot combustion was evaluated， and the cyclic stability was tested. The results show that the loading mode of the active component Mn has a great influence on the structure and properties of the catalyst. The interaction between Cu and Mn species is regulated by the M—O bond， which affects the ability to activate oxygen and NO， as well as the migration of lattice oxygen. Compared to the 3% Mn-3% Cu/γ-Al2O3 catalyst prepared by impregnation（imp）， the 3% Mn-3% Cu/γ-Al2O3 catalyst prepared by deposition precipitation（dp） exhibited enhanced interactions between CuOz and MnOz， leading to a rich surface presence of Mn4+/Mn3+ as well as surface-adsorbed oxygen species， thus improving soot combustion performance. In NO presence， the T50 （temperature at 50% conversion of soot） for soot combustion was reduced by 104 ℃. Moreover， the introduction of an appropriate amount of alkali metal Na facilitates electron transfer between Cu and Mn species， increasing the mobility of oxygen species and enhancing soot combustion activity.