EPR characterisation of carbon black in loose and tight contact with Al2O3 and CeO2 catalysts

The intensity of contact between soot and catalyst is one of the major parameters that determine the soot oxidation reactivity. In the present work the EPR study is focused on the mixtures of carbon black with Al2O3 and CeO2 in loose and tight contacts in order to provide the physicochemical characterisation of the contact. For tight contact CB-catalyst mixtures a new paramagnetic species is observed and can be considered as a fingerprint of the contact between the two solids. These new paramagnetic species increase the catalytic reactivity of CB combustion in the presence of cerium oxide.