In-situ XAS Study of Catalytic N2O Decomposition Over CuO/CeO2 Catalysts

Abstract

We performed in-situ XAS study of N₂O decomposition over CuO/CeO₂ catalysts. The Cu K-edge and Ce L₃-edge XANES and EXAFS analyses revealed the dynamic and crucial role of Cu²⁺/Cu⁺ and Ce⁴⁺/Ce³⁺ ionic pairs during the catalytic reaction. We observed the initial formation of reduced Cu⁺ and Ce³⁺ species during activation in helium atmosphere at 400 °C, while concentration of these species decreased significantly during steady-state nitrous oxide degradation reaction (2500 ppm N₂O in He at 400 °C). In-situ EXAFS analysis further revealed a crucial role of copper−ceria interface in this catalytic reaction. We observed dynamic changes in average number of Cu−Ce scatters under reaction conditions, indicating an enlarging of the interface between both copper and ceria phases, where electron and oxygen transfer occurs.