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

Abstract

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 catal...