Operando XAS and XRD measurements to elucidate the deactivation / reactivation behaviour of Pt-Pd/CeO2 bimetallic catalysts for CH4 oxidatio

This study aims at the fundamental understanding of the deactivation/recativation behaviour of Pt-Pd/CeO2 catalysts for CH4 oxidation. Such bimetallic catalysts are typically used for emission reduction in the exhaust of heat and power plants but the fundamental understanding of their evolution under reaction conditions is still lacking. This is caused partially by the rather heterogeneous catalyst structure obtained by conventional preparation methods. Starting with well-defined and alloyed Pt-Pd NPs of different sizes, the evolution of each noble metal will be monitored by in situ/operando XAS at Pt L3 and Pd K edges and XRD measurements while exposing the catalysts to progressively higher temperatures. This will help to identify segregation and de-alloying processes as well as the formation of highly dispersed Pt and Pd species, which lead to catalyst deactivation. In a next step, the re-alloying process will be investigated as a function of catalyst reactivation conditions.