Isotopic transient kinetic study of N2O decomposition on LaMnO3 + δ

• Lattice oxygen of perovskites participates in N2O decomposition.
• Correlation exists between oxygen exchange properties and rate of N2O decomposition.
• Surface oxygen vacancies plays an important role in reactivity of perovskites.
• Activity correlates with bulk oxygen diffusion when surface vacancies are limited.

Analysis of label oxygen transfer during the reaction of N2O decomposition (18O2/N216O) on LaMnO3 + δ indicated that 16O transfer from N216O to 16O2 preceded faster compared to oxygen exchange 18O2/16O2 and involved the interaction with two lattice oxygen of perovskite. It suggests that surface oxygen vacancies play an important role in reactivity of LaMnO3 and explains why at times correlation can be found between catalytic activity and bulk oxygen diffusion (La1 − xSrxMnO3 ± δ) and at other time catalytic properties correlate with surface oxygen exchange constant (La1−xSrxFeO3−θ). The former can be due to general correspondence between surface oxygen exchange kinetics and bulk oxygen diffusion.

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