Methane partial oxidation (MOP) chemically transforms natural gas to syngas for production of gasoline. CeO2 doped with transition metal ions is a type of catalyst active for MPO. Fundamental understanding of MP O on this type of catalysis is important for the development of catalysts of MPO process. Pd, Pt, or Rh doped CeO2 catalysts were prepared through doping their ions in CeO2 nanoparticles during synthesis. Catalytic activity and selectivity in production of H2 and CO through methane partial oxidation (MPO) on these ceria-based catalysts and their surface chemistries during catalysis were investigated. They exhibit different catalytic performances in MPO. In-situ studies of surface chemistry those catalysts during catalysis using ambient pressure X-ray photoelectron spectroscopy (AP-XPS) revealed quite different surface chemistries of the Pd, Pt, or Rh doped CeO2 catalysts during catalysis. A correlation between their catalytic performances and the corresponding surface chemistries at different temperatures  was built. Rh in Rh-doped CeO2 catalyst remains oxidizing state during catalysis in the whole temperature regime. In contrast to Rh, Pt and Pd exist in the format of both metallic and oxidizing states during catalysis. Correlation between in-situ surface chemistry and the corresponding catalytic performance shows that Rh ions, Pt ions, and metallic Pd are components of active sites on Rh-CeO2, Pt-CeO2 and Pd-CeO2 catalysts during catalysis, respectively. Among these catalysts Rh-doped CeO2 exhibits highest catalytic activity and selectivity in MPO.

Catalytic performances and in-situ surface chemistries of ceria doped with palladium, platinum, and rhodium in methane partial oxidation for production of syngas

246th National Meeting (2013)

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