Constructing three-dimensionally ordered macroporous LaCrOδ composite oxide via cerium substitution for enhanced soot abatement
La1-xCexCrOδ (0≤x≤0.3) composite oxides with three-dimensionally ordered macroporous (3DOM) structure were constructed by colloidal crystal template method and characterized by XRD, FT-IR, FESEM, N2 adsorption-desorption, XPS, H2-TPR and O2-TPD techniques. The catalytic performances of the as-prepared samples for soot oxidation were further evaluated. In the case of the unsubstituted one, the crystal size of LaCrO3 increased along with the rising calcination temperature, which resulting in the destruction of the 3DOM structure. The introduction of Ce delayed the crystal phase transition from LaCrO4 monazite to LaCrO3 perovskite and inhibited the growth of the crystal size, and thus the collapse of the 3DOM structure was inhibited. Meanwhile, the concentration of active and lattice oxygen species was further enhanced. The optimization of the structure and intrinsic properties of the catalyst impels the enhancement of their catalytic performance for soot removal.