Insight into the effect of catalytic reactions on correlations of soot oxidation activity and microspatial structures*

A catalyst is usually coated on Diesel particulate filter (DPF) for assisted regeneration. In this paper, the oxidation activity and pore structure evolutions of soot under the effect of CeO2 are explored. CeO2 effectively increases the oxidation activity of soot and reduces the initial activation energy; in the meantime, the addition of CeO2 changes the soot oxidation mode. Pure soot particles tend to produce the porous structure in the oxidation process. Mesopores promote the diffusion of oxygen, and macropores contribute to reduce the agglomeration of soot particles. Additionally, CeO2 provides the active oxygen for soot oxidation and promotes the multi-point oxidation at the beginning of soot oxidation. With the oxidation proceeding, catalysis causes the collapsion of soot microspatial structures, in the meantime, the macropores caused by the catalytic oxidation are filled by CeO2. It results in the tight contact between soot and catalyst, further promoting the formation of the available active oxygen for soot oxidation. This paper is meaningful to analyze the oxidation mechanism of soot under catalysis, which lays a foundation for improving the regeneration efficiency of DPF and reducing the particle emission.

Automated summary

This paper investigates the effects of CeO2 on the oxidation activity and pore structure evolution of soot. CeO2 effectively enhances the oxidation activity of soot and lowers the initial activation energy. Moreover, CeO2 alters the oxidative mode of soot. Pure soot particles tend to develop a porous structure during oxidation, with mesopores facilitating oxygen diffusion and macropores preventing soot particle agglomeration. Additionally, CeO2 supplies active oxygen for soot oxidation and promotes multi-point oxidation in the beginning stages. The catalytic process causes the collapse of soot microspatial structures and the macropores formed by catalytic oxidation are filled by CeO2, resulting in closer contact between soot and catalyst and further enhancing the production of available oxygen for soot oxidation. This study is significant for understanding the oxidation mechanism of soot under catalysis, thereby providing a foundation for improving DPF regeneration efficiency and reducing particle emissions.