Reactive Oxygen Pool over Ceria Enables Catalytic Oscillation

Heterogeneous catalytic reactions often exhibit kinetic oscillations—spontaneous, non-equilibrium phenomena occurring across various reaction systems. Despite decades of investigations, the mechanisms that initiate and sustain these oscillations remain elusive. Here we report the discovery of unexpected kinetic oscillations over Pt/CeO ₂ catalysts during the competitive oxidation of hydrogen and carbon monoxide at approximately 60°C. Through operando characterization and first-principles mathematical analysis, we uncover the underlying mechanism and existence conditions of oscillations, demonstrating that these oscillations are governed by periodic cycles of ceria reduction and oxidation, gated by CO coverage on Pt. This represents the first demonstration that the reactive oxygen pool of the support can actively induce and sustain catalytic oscillations. These findings redefine metal-support synergy and provide a theoretical formalism for understanding complex non-equilibrium phenomena in heterogeneous catalysis.