Raman Observation of the Chemical State of Ru/CeO 2 Catalysts

ABSTRACT The chemical transformations of CeO 2 and Ru/CeO 2 catalysts under oxidative treatment (i.e., typical conditions of oxidation reactions on metal/oxide catalysts) were investigated using in situ Raman spectroscopy, and complemented by near‐ambient pressure X‐ray photoelectron spectroscopy (NAP‐XPS). The main attention was focused on the Raman study of the effect of Ru loadinag degree on the structure of CeO 2 support in Ru/CeO 2 catalysts undergoing oxidative treatment. The advances and limitations of Raman spectroscopy for studying the chemical state of Ru/CeO 2 catalysts were systematically investigated and discussed, demonstrating its high potential to monitoring the physicochemical state of ceria support in the Ru/CeO 2 system. The limited applicability of Raman spectroscopy for monitoring the Ru species in Ru/CeO 2 catalyst was also demonstrated.