Ceria-zirconia particles wrapped in a 2D carbon envelope: improved low-temperature oxygen transfer and oxidation activity

Abstract

Engineering the interface between different compo-nents of heterogeneous catalysts at nanometer level canradically alter their performances.This is particularly true forceria-based catalysts where the interactions are critical forobtaining materials with enhanced properties.Here we showthat mechanical contact achieved by high-energy milling ofCeO2–ZrO2powders and carbon soot results in the formationof acore of oxide particles wrapped in athin carbon envelope.This 2D nanoscale carbon arrangement greatly increases thenumber and quality of contact points between the oxide andcarbon. Consequently,the temperatures of activation andtransfer of the oxygen in ceria are shifted to exceptionally lowtemperatures and the soot combustion rate is boosted. Thestudy confirms the importance of the redox behavior of ceria-zirconia particles in the mechanism of soot oxidation andshows that the organization of contact points at the nanoscalecan significantly modify the reactivity resulting in unexpectedproperties and functionalities.