Mechanism of Suppression of Carbon Deposition on the Pd−Ni/Ce(Sm)O2−La(Sr)CrO3 Anode in Dry CH4 Fuel

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• 作者：Yuta Nabae ; Ichiro Yamanaka ; Masaharu Hatano ; Kiyoshi Otsuka
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：July 10, 2008
• 年：2008
• 卷：112
• 期：27
• 页码：10308 - 10315
• 全文大小：1185K
• 年卷期：v.112,no.27(July 10, 2008)
• ISSN：1932-7455

文摘

Catalytic properties of Pd−Ni catalysts were studied to clarify the mechanism of suppression of carbon deposition on a Pd−Ni catalyst supported on a composite of Ce(Sm)O₂ and La(Sr)CrO₃, which is a promising anode material for direct oxidation of dry CH₄ in solid oxide fuel cells (SOFCs). The catalytic activity of Pd−Ni catalysts for the carbon formation in the decomposition of CH₄ was found to be strongly dependent on the support materials. Carbon deposition was remarkably suppressed on Pd−Ni/Ce(Sm)O₂ and Pd−Ni/La(Sr)CrO₃ catalysts, whereas Pd−Ni/SiO₂ and Pd−Ni/carbon catalysts were very active for the formation of carbon nanofibers. TEM analysis showed the morphology of the Pd−Ni particles and carbon deposit on the Pd−Ni/Ce(Sm)O₂ catalyst was quite different from that on the Pd−Ni/C catalyst. XRD and TEM-EDS analysis indicate that Ce and Sm were doped into the Pd−Ni alloy from the Ce(Sm)O₂ supports. High catalytic activity of the Pd−Ni/Ce(Sm)O₂ catalyst for steam reforming indicates that the Pd−Ni catalysts modified with Ce still have high catalytic activity for the activation of CH₄. A model for the mechanism of the suppression of the carbon deposition on the Pd−Ni catalyst is proposed focusing on the formation mechanism of the carbon deposit. The high catalytic activity of the Pd−Ni alloy for the activation of CH₄ and the high tolerance to carbon deposition deriving from the doping are suitable for direct utilization of dry CH₄ over SOFC anodes.