Low-temperature oxidation of methane over pd supported on SnO2-based oxides

Article abstract of DOI:10.1246/bcsj.72.313

Pd catalysts supported on various metal oxides were investigated for the low-temperature catalytic combustion of methane. Of the catalysts examined, a Pd/SnO₂ catalyst demonstrated excellent activity despite its low specific surface area. The activity of the Pd/SnO₂ catalyst was lowered with the addition of M (= Al, Ce, Fe, Mn, Ni, and Zr) oxide to the support, Pd/SnO₂- MO(x). It was observed by a transmission electron-microscope observation that the PdO phase was well-dispersed on the outer surface of SnO₂ support uniformly, observed as an intimately contacted layer on fine SnO₂ particles. The temperature-programmed desorption of oxygen has revealed that the catalytic activity depends on the adsorption state of oxygen on palladium. An X-ray photoelectron spectroscopic analysis suggested that reduction of the palladium surface proceeded slowly under a strong palladium-support interaction for Pd/SnO₂. In situ X-ray diffraction indicated that the PdO phase was stabilized at higher temperature on SnO₂ than on the Al₂O₃ support. It is considered that the catalytic activity is strongly influenced by the interaction between palladium and SnO₂. Pd catalysts supported on various metal oxides were investigated for the low-temperature catalytic combustion of methane. Of the catalysts examined, a Pd/SnO₂ catalyst demonstrated excellent activity despite its low specific surface area. The activity of the Pd/SnO₂ catalyst was lowered with the addition of M (= Al, Ce, Fe, Mn, Ni, and Zr) oxide to the support, Pd/SnO₂-MO_x. It was observed by a transmission electron-microscope observation that the PdO phase was well-dispersed on the outer surface of SnO₂ support uniformly, observed as an intimately contacted layer on fine SnO₂ particles. The temperature-programmed desorption of oxygen has revealed that the catalytic activity depends on the adsorption state of oxygen on palladium. An X-ray photoelectron spectroscopic analysis suggested that reduction of the palladium surface proceeded slowly under a strong palladium-support interaction for Pd/SnO₂. In situ X-ray diffraction indicated that the PdO phase was stabilized at higher temperature on SnO₂ than on the Al₂0₃ support. It is considered that the catalytic activity is strongly influenced by the interaction between palladium and SnO₂.