To Coke or Not to Coke: When Pd Is Not Noble Anymore under Methane Dry Reforming Conditions

We explore the fundamental pathways of carbon formation and regeneration in a model Pd/Zr catalyst during dry reforming of methane (DRM) and under related reaction conditions. Using a combination of XPS, SEM, and EDX, we track the structural and chemical changes of the catalyst throughout the reaction, deactivation, and regeneration cycles. By systematically adjusting feed composition, CO₂ conversion, and regeneration atmospheres, the study identifies how different gas-phase species contribute to carbon formation and clean-off. It also determines the conditions that influence the accessibility of the reactive metal-oxide interfaces. A comparison with the analogous Ni/Zr system highlights how the choice of the metal affects regeneration chemistry and the importance of accessible metal oxide phase boundaries in CO₂ activation. The experimental setup combines temperature-resolved reaction profiling with micro- and spectroscopic surface characterization at key intermediate stages, enabling direct links among catalytic activity, surface morphology, and regeneration results. This approach offers insights into how catalyst design, operational conditions, and regeneration methods can be optimized to achieve high DRM activity and effective carbon management in noble metal-oxide systems.