Heterogeneous oxidation of powder and individual carbon nanoparticles catalyzed by ceria nanoparticles

Abstract

To comply with stricter regulations on particulate emissions, ceria based catalyst has been researched in developing diesel particulate filters. Here chemical reaction parameters are determined experimentally for CeO2-nanoparticle catalyzed soot oxidation for two representative environments: a bulk process with a catalyst/carbon mixture and individual carbon-nanoparticles attached to CeO2. The first task was carried out in simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) experiments, while the second was performed with in-situ environmental scanning transmission electron microscopy (ESTEM). The TGA/DSC results suggested the role of gas diffusion through the porous sample was significant and slowed down the reaction rate. The ESTEM videos affirmed the catalyzed reaction resulted in a higher oxidation rate at the contact area between CeO2 and carbon, which caused the movement of carbon nanoparticles towards CeO2. Measured reaction kinetics data were compared to the Darcy’s model and their discrepancies were elaborated.