Design of an Ultrastable and Highly Active Ceria Catalyst for CO Oxidation by Rare-Earth- and Transition-Metal Co-Doping

Catalyst design with good stability beyond simply having high activity is crucial for a variety of reactions. Here, we evaluate the ceria catalyst for CO oxidation as a model reaction to rationally design an ultrastable catalyst with high activity. The goal was achieved by co-doping with rare-earth (RE) and transition metals (TM) simultaneously. The RE dopant stabilized the catalyst by inhibiting sintering that could lead to catalyst deactivation. The TM dopant increased the activity by facilitating formation of surface defects. Consequently, ceria co-doped with RE (=La, Sm) and TM (=Cu) had increased catalytic activity as well as superior resistance to deactivation during 10 cycle measurement (1 cycle: 900 °C, 24 h → cooling at room temperature → target °C, 24 h) of ∼700 h, which is harsher than any other reported conditions. This approach will shed light on the design of ultrastable oxide materials for a wide range of catalytic reactions.