Preparation of cordierite-supported particulate matter filters and Sm2-xCexZr2O7 monolithic catalysts for soot catalytic oxidation

We synthesized magnesium borate whiskers via a precipitation molten-salt method. We subsequently loaded the Sm 2-x Ce x Zr 2 O 7 catalysts onto the whiskers through precipitation to mimic the hierarchical microstructure of respiratory cilia. The optimal microstructure was achieved with a B:Mg molar ratio of 3:2, yielding whiskers with an aspect ratio (length/diameter) of 42.107. It is clear that the growth of these whiskers on porous cordierite ceramics significantly enhances the specific surface area and soot filtration efficiency. Binding strength tests confirm the robust adhesion of whiskers to the ceramic substrate. H 2 -TPR and O 2 -TPD analyses definitively reveal that Ce-doped catalysts (Sm 1.9 Ce 0.1 Zr 2 O 7 ) possess higher surface-active oxygen content, improve lattice oxygen mobility, and increased oxygen vacancies, leading to superior catalytic activity. XPS further validated the valence states of surface elements. Density functional theory (DFT) calculations prove that Ce doping increases the surface energy of the (222), (400), and (440) crystal planes, while reducing the oxygen vacancy formation energy. This enhances the catalytic combustion performance via the Mars-van Krevelen mechanism. The Z -Sm 1.9 Ce 0.1 Zr 2 O 7 catalysts have been shown to exhibit exceptional soot oxidation performance, lowering the ignition temperature (T 10 ) to 375 °C and the peak combustion temperature (T 50 ) to 425 °C. Cyclic stability tests demonstrate sustained structural integrity and catalytic efficiency. This unique microstructure shows clear potential for diesel particulate filter applications.