Abstract: Studying the kinetics of CO oxidation over Pd foil, we observed an inverse hysteresis: CO conversion was much lower under sample cooling than under foil heating. It was established that under heating the oxidation of metallic Pd (Pd0) to bulk PdO (PdOb) occurred through formation of the surface oxide PdO (PdOs). Under cooling PdOb reduced directly to Pd0 species, and in this case the self-sustained oscillations of reaction rate were observed. To describe reverse hysteresis together with oscillations the original kinetic model of CO oxidation reaction is proposed on the base of Langmuir-Hinshelwood mechanism both on Pd0 and PdOs surfaces. In this work we developed new approach based on nonlinear dependence of the activation energy of CO-oxygen interaction on coverage and composition of oxygen species over the catalyst surface. Under such assumptions, the model is capable to describe inverse hysteresis of CO oxidation rate as well as its oscillatory behavior at constant temperature.

Cite: Lashina E.A. , Slavinskaya E.M. , Chumakova N.A. , Chumakov G.A. , Stadnichenko A.I. , Boronin A.I.
Inverse Hysteresis and Self-Sustained Oscillations of CO Oxidation Reaction Rate over Pd Foil
In compilation 13th European Congress on Catalysis. 2017. – C.306-307.

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