Ordered macro-mesoporous nanostructure of Pd/ZrO2 catalyst for boosting
catalytic soot oxidation
Abstract
ABSTRACT: Herein, the hierarchical porous catalysts of three dimensional
ordered macro-mesoporous (3DOMM) ZrO2-supported active Pd nanoparticles
(NPs) were prepared by two-step methods of evaporation-induced
self-assembly-colloid crystal template (EISA-CCT) and gas
bubbling-assisted membrane reduction (GBMR). Ordered macroporous
structure can enhance diffusion and mass transfer of soot particles;
ordered mesoporous structure is beneficial to enhancing activation
ability for gaseous reactants. Synergistic effect of hierarchical porous
structure in the catalysts is important to improve catalytic activity
for soot oxidation. Pd/3DOMM-ZrO2 catalyst exhibits the highest activity
(T50=404 oC) for soot oxidation compared with the single macroporous or
mesoporous structure. The catalytic kinetics of hierarchical porous
Pd/3DOMM-ZrO2 catalyst for soot oxidation was systemically investigated,
i.e., its reaction rate is 0.038 μmolg-1s-1 at 310 oC, which is 2.7-fold
of power-type Pd/normal-ZrO2 catalyst (0.014 μmolg-1s-1). The
hierarchical porous structure is a good strategy to boost catalytic
activity during soot oxidation.