Partial oxidation of methane on Pt-supported lanthanide doped ceria-zirconia oxides: Effect of the surface/lattice oxygen mobility on catalytic performance

作者：Sadykov Vladislav A^*; Sazonova Nathalia N; Bobin Aleksei S; Muzykantov Vitalii S; Gubanova Elena L; Alikina Galina M; Lukashevich Anton I; Rogov Vladimir A; Ermakova Eugenia N; Sadovskaya Ekaterina M; Mezentseva Nathalia V; Zevak Ekaterina G; Veniaminov Sergei A; Muhler Martin; Mirodatos Claude; Schuurman Yves; van Veen Andre C

来源：Catalysis Today, 2011, 169(1): 125-137.

DOI：10.1016/j.cattod.2010.10.098

• Selective oxidation of CH(4)
• Syngas
• Pt
• Fluorite-like oxides
• Oxygen mobility and reactivity
• Oxygen isotope exchange
• Transient studies
• Mechanism

Partial oxidation of methane into syngas at short contact times (5-15 ms) was studied in both steady-state and transient modes at temperatures up to 850 degrees C in realistic feeds (CH(4) content up to 20%, CH(4)/O(2) = 2) with a minimum impact of mass and heat transfer for structured catalysts carrying Pt/Ln(0.3)Ce(0.35)Zr(0.35)O(2-y) (Ln = La, Pr, Gd) as thin layers on walls of corundum channel substrates. Oxygen mobility and reactivity of the active phase were characterized by oxygen isotope heteroexchange, temperature-programmed O(2) desorption and CH(4) reduction, isothermal pulse reduction by methane with wide variation of CH(4) concentrations and TAP pulse studies. Experimental data point towards a selective oxidation of methane into syngas via a direct route with oxygen-assisted methane activation. This mechanistic feature is related to the strong Pt-support interaction stabilizing highly dispersed oxidic Pt species less active in CH(4) and syngas combustion than metallic Pt clusters. Support activates O(2) molecules and supplies active oxygen species to Pt sites. A high rate of oxygen diffusion on the surface and in the bulk of the support and Pt-support oxygen spillover stabilizes Pt in a well dispersed partially oxidized state while preventing coking at high concentrations of CH(4) in the feed.

• 出版日期2011-7