Oxidising CO to CO2 using ceria nanoparticles

Abstract

We calculate, using simulated amorphisation and recrystallisation (A&R), that ceria (CeO₂) nanoparticles, about 8 nm in diameter, comprise a high concentration of labile surface oxygen species, which we suggest will help promote the oxidation of CO to CO₂. In particular, the ceria nanoparticle contains a high proportion of reactive {100} surfaces, surface steps and corner sites. When reduced to CeO_1.95, the associated Ce³⁺ species and oxygen vacancies decorate step, corner and {100} sites in addition to plateau positions on {111}. The energetics of CO oxidation to CO₂, catalysed by a ceria nanoparticle, is calculated to be lower compared with CO oxidation associated with the lowest energy surface (i.e. CeO₂(111)) of the corresponding ‘bulk’ material. Our calculated morphologies for the ceria nanoparticles are in accord with experiment.