Redox-Activated\nSupersaturation of Ceria Solid Solution as a Dynamic Catalyst Enabling\nLow-Temperature Ethylbenzene Oxidative Dehydrogenation

Dynamic structural changes in the\nreactive environment\noften lead to catalyst deactivation in the thermal-catalysis field.\nTaking advantage of the dynamic changes in bulk phases, interfaces,\nand surface structures to design highly active catalysts is a unique\nbut important strategy. Herein, we report a supersaturated ceria solid\nsolution catalyst enabling a styrene yield of 91.8% over extended\nredox cycles at 430 °C in the redox oxidative dehydrogenation\n(ODH) of ethylbenzene. In-situ characterizations reveal that the oxygen\nanions (O<sup>2–</sup>) and transition-metal cations (Fe and\nMn) reversibly shuttle through a ceria solid solution (bulk ↔\nsurface) in a K–Ce<sub>0.47</sub>Fe<sub>0.2</sub>Mn<sub>0.33</sub>O<sub>2−δ</sub> catalyst during the redox ODH process.\nThe ceria solid solution acts as a dynamic transition-metal cations/oxygen\nreservoir, creating atomic interfaces of K–Fe–O/K–Mn–O\nand an oxygen gateway for efficient ethylbenzene ODH. The findings\nconcerning the formation of a supersaturated ceria solid solution\nand cations, lattice oxygen migration, and the coupling between oxygen\ndonation and catalytic reactions offer new strategies for designing\nhigh-performance dynamic catalysts.