Operando XAS/XRD study during pulsed and long-term activation and tests of Pd/CeO2-ZrO2 catalysts with varying loading for methane oxidation

In order to optimize the content of the expensive noble metal (NM) and retain high stability and low-temperature activity of catalysts, this study aims at studying structure-activity relationships in Pd/CeO2-ZrO2 catalysts for CH4 oxidation. This will be achieved by exploiting the strong metal-support interaction in this system and the ability to tune the noble metal speciation (particle size, oxidation state) by systematically applying various oxidative (O2) and reductive (CO, CH4) treatments. By means of in situ XAS and XRD measurements, the goal of the present study is to reveal structural changes of Pd, i.e. oxidation state and particle size (XAS), and CeO2-ZrO2 support, i.e. reduction of the mixed oxide (XRD, supported by XAS), that are caused during various reducing treatments. Next, the activity and stability of the samples will be monitored during successive light-off/light-out cycles and correlated with simultaneous operando XAS and XRD data on Pd and CeO2-ZrO2 supports.