Self-sustained oscillations in CO oxidation reaction on PdO/Al2O3 catalyst

The paper presents the experimental study and mathematical modeling of self-sustained oscillations in the reaction of CO oxidation on PdO/Al2O3 catalysts. In experiments we observe the complicated multi-peak oscillatory behavior of CO conversion under isothermal conditions. At these, the palladium surface is composed of a mixture of the metallic and oxide phases. We develop some new mathematical models describing the interaction of reagents with the Pd and PdO surfaces and taking into account the influence of the reaction medium on the catalyst activity. The models qualitatively describe the relaxation and multi-peak oscillations of the CO conversion. The redox process of Pd–PdO transition observed in the experiment causes the relaxation oscillations, while the mixed-mode oscillations in the model are observed due to coupling between the deep oxidation of palladium and the surface modification by oxygen.

► Self-oscillations in CO oxidation on PdO/Al2O3 catalysts are under study.
► Dynamical experiments show isothermal multi-peak oscillations of CO conversion.
► The catalyst surface is composed of a mixture of the metallic Pd and oxide phases.
► New mathematical models account for varying catalyst activity in reaction conditions.
► The models qualitatively describe relaxation behavior and multi-peak oscillations.