Three-dimensional Ordered Macroporous Orderedmesoporous Ce-Zr Solid Solution Based Catalysts For The Catalytic Combustion Of Soot

Soot particles are one of the main components of atmospheric PM2.5,and the elimination or reduction of diesel exhaust particles has considered to be the key to solving this problem.In this thesis work,the ordered mesoporous structure on the three-dimensional ordered macroporous Ce-Zr solid solution materials were successfully prepared.The obtained new three-dimensional ordered macroporous-ordered mesoporous?3DOMM?Ce-Zr solid solution material has a surface area of 239.9 m²g^-1,which is 7-10 times that of the conventional 3DOM material,and it exhibits excellent performance for soot combustion.After screening the optimal carrier by activity,we loaded Co₃O₄,Mn₂O₃ and Ce O₂ to compare their activities.The catalysts and physico-chemical properties were explored by means of XRD,BET,SEM,TEM,H₂-TPR,NO-TPO and so on.The activity of 3DOMM Ce_0.4Zr_0.6O₂ supported 30%Co₃O₄ was the best,and the T₅₀ reached 355°C.This is a very low temperature for non-noble metal catalyst catalyzed soot combustion.The NO-TPO results show that although the reaction between the solids,like catalytic soot combustion,reaches an upper limit of activity.However,for the oxidation of NO to produce NO₂,the material loading amount does not reach the upper limit.It provides more possibilities for 3DOMM materials.In this thesis work,3DOM Ce_0.8Co_0.1Zr_0.1O₂ catalyst was also prepared and the transition metal Mn or Co doping method was chosen to investigate the effect of doping amount on the activity of the catalyst.It is worth noting that after the catalyst is doped with Mn,Mn enters the interior of the crystal lattice and no longer forms Mn O_X species on the surface.However,doping Co not only causes Co to enter the interior of the crystal lattice,but also forms Co O_X species on the surface of the catalyst.From the overall activity and selectivity to CO₂,3DOM Ce_0.85Mn_0.05Z_r0.1O₂ is the best in the Mn-doped catalysts,the T₅₀reaches 352°C,and the selectivity reaches 99.4%.Among the Co-doped catalysts,3DOM Ce_0.8Co_0.1Zr_0.1O₂ was the most preferable,the T₅₀ was 384°C,and the selectivity was 99.6%.We believe that the activity of Co-doped cerium-zirconium solid solution catalyst has room for further improvement.