Crystallinityof Cerium Oxide Dictates Reactivityof Platinum Catalysts

The reactivity of supported metal catalysts can be influenced by the nature of supports, which synergistically activate reactant molecules with metal sites. The investigation of the crystalline effect of CeO₂ remains unclear because of the easy formation of fluorite-structure CeO₂. Here, we successfully synthesized CeO_<i>x</i> clusters with distinct crystallinity and established that the crystalline nature of CeO_<i>x</i> clusters dictates the reactivity of the Pt/CeO_<i>x</i> catalysts for CO oxidation. Specifically, Pt clusters supported on crystalline CeO_<i>x</i> exhibited a specific CO conversion rate approximately 15-fold higher than those on amorphous CeO_<i>x</i> at temperatures of 120 to 140 °C. Detailed experimental investigations and simulations revealed that the enhanced CO oxidation reactivity originates from the higher mobility of lattice oxygen and more labile oxygen species on crystalline CeO_<i>x</i> nanoclusters. This work deepens our understanding of crystallinity-dependent redox properties of nanoscale oxide supports and opens new routes for designing better metal catalysts for targeted reactions.