Crystallinity of Cerium Oxide Dictates Reactivity of 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 CeOx clusters with distinct crystallinity and established that the crystalline nature of CeOx clusters dictates the reactivity of the Pt/CeOx catalysts for CO oxidation. Specifically, Pt clusters supported on crystalline CeOx exhibited a specific CO conversion rate approximately 15-fold higher than those on amorphous CeOx 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 CeOx 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.