TY - JOUR

T1 - Kinetics of Oxygen Exchange and N2O Decomposition Reaction over MeOx/CeO2 (Me = Fe, Co, Ni) Catalysts

AU - Sadovskaya, Ekaterina

AU - Pinaeva, Larisa

AU - Skazka, Valerii

AU - Prosvirin, Igor

N1 - 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).

PY - 2023/1/18

Y1 - 2023/1/18

N2 - MeOx/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 (RI) and two-atom (RII) 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 MeOx to CeOx 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 FeOx/CeO2 samples with a different iron content.

AB - MeOx/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 (RI) and two-atom (RII) 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 MeOx to CeOx 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 FeOx/CeO2 samples with a different iron content.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85147851085&origin=inward&txGid=6c8a9a06f31c15af8f2270f352c84399

UR - https://www.mendeley.com/catalogue/516bac37-053b-3c14-8951-268dddbd4f24/

U2 - 10.3390/ma16030929

DO - 10.3390/ma16030929

M3 - Article

C2 - 36769936

VL - 16

JO - Materials

JF - Materials

SN - 1996-1944

IS - 3

M1 - 929

ER -