Ceria-catalyzed soot oxidation studied by environmental transmission electron microscopy

Environmental transmission electron microscopy (ETEM) was used to monitor in situ ceria-catalyzed oxidation of soot in relation to diesel engine emission control. From time-lapsed ETEM image series of soot particles in contact with CeO2, or with Al2O3 as inert reference, mechanistic and kinetic insight into the catalytic and noncatalytic oxidation mechanisms was obtained. Specifically, the results indicate that the catalytic soot oxidation mechanism involves reaction centers at the soot–CeO2 interface and that the interface reaction kinetic properties are in good agreement with previous macroscopic, averaging measurements.