Kinetics of Oxygen Exchange and N2O Decomposition Reaction over MeOx/CeO2 (Me = Fe, Co, Ni) Catalysts

Ekaterina Sadovskaya; Larisa Pinaeva; Valerii Skazka; Igor Prosvirin

doi:10.3390/ma16030929

Kinetics of Oxygen Exchange and N₂O Decomposition Reaction over MeO_x/CeO₂ (Me = Fe, Co, Ni) Catalysts

Materials (Basel). 2023 Jan 18;16(3):929. doi: 10.3390/ma16030929.

Authors

Ekaterina Sadovskaya¹, Larisa Pinaeva¹, Valerii Skazka², Igor Prosvirin¹

Affiliations

¹ Boreskov Institute of Catalysis SB RAS, 5, Lavrentiev Ave., 630090 Novosibirsk, Russia.
² Department of Mathematics and Mechanics, Novosibirsk State University, 2, Pirogov Str., 630090 Novosibirsk, Russia.

Abstract

MeO_x/CeO₂ (Me = Fe, Co, Ni) samples were tested in an ¹⁸O₂ temperature-programmed isotope exchange and N₂O decomposition (deN₂O). A decrease in the rate of deN₂O in the presence of oxygen evidences the competitive adsorption of N₂O and O₂ on the same sites. A study of isotope oxygen exchange revealed dissociative oxygen adsorption with the subsequent formation of surface oxygen species. The same species, more probably, result from N₂O adsorption and the following N₂ evolution to the gas phase. We supposed the same mechanism of O₂ formation from surface oxygen species in both reactions, including the stages responsible for its mobility. A detailed analysis of the kinetics of isotope exchange has been performed, and the rates of one-atom (R^I) and two-atom (R^II) types of exchange were evaluated. The rate of the stage characterizing the mobility of surface oxygen was calculated, supposing the same two-step mechanism was relevant for both types of exchange. The effect of oxygen mobility on the kinetics of deN₂O was estimated. An analysis of the possible pathways of isotope transfer from MeO_x to CeO_x showed that direct oxygen exchange on the Me-Ce interface makes a valuable contribution to the rate of this reaction. The principal role of the Me-Ce interface in deN₂O was confirmed with independent experiments on FeO_x/CeO₂ samples with a different iron content.

Keywords: Me–Ce interface; oxygen mobility; surface; temperature programmed isotope exchange.

Grants and funding

This work was supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental order for the Boreskov Institute of Catalysis (project AAAA-A21-121011390010-7).