Abstract:U.S. Department of Energy [FG07-01AL67358, DE-FC07-06ID14781]In order to study the chemical interaction during interface formation between Pd and SiC, Pd layers of various thicknesses were deposited on structurally disordered SiC surfaces at 800 degrees C. The Pd/SiC interface, which plays a crucial role for many applications such as high power electronic devices and tristructural-isotropic (TRISO) nuclear fuels, was studied in situ by x-ray photoelectron spectroscopy. We find that after Pd deposition, Si-C an… Show more
“…Thus, two peaks were fitted using the same peak shape as above (30:70 Gaussian-Lorentzian) one peak corresponding to adventitious carbon at a BE of 284.6 eV and a peak at BE = 281.5 eV. [24,32] The peak at 281.5 eV most likely originates from the formation of carbide-like species. We cannot exclude the possibility of aluminium carbide formation, but suggest aluminium carbide formation to be un-likely, due to a constant FWHM of the Al 2p line for the coked and uncoked sample which suggests absence of any aluminium phases other than oxide.…”
Section: The Nature Of the Sites Active In Methane Combustionmentioning
The catalytic combustion of <1 % methane in air over palladium‐based catalysts is investigated. The influence of operating parameters and pretreatment conditions on the activity and stability of the catalysts is studied. X‐ray photoelectron spectroscopy analysis of Pd/Al2O3 indicates the emergence of Pd carbide, even under lean conditions (0.6 % methane) and at temperatures as low as 180 °C. Significant differences were observed in the light‐off temperatures and extent of coke deposition, depending on whether the catalysts were conditioned under oxidizing or reducing conditions. The oxidized palladium catalysts were reduced by methane under reaction conditions and exhibited similar activity compared to catalysts which were activated under hydrogen. Time‐on‐stream experiments reveal that the stability of the Pd/Al2O3 catalyst reduced in hydrogen was only marginally improved compared to catalysts calcined in air.
“…Thus, two peaks were fitted using the same peak shape as above (30:70 Gaussian-Lorentzian) one peak corresponding to adventitious carbon at a BE of 284.6 eV and a peak at BE = 281.5 eV. [24,32] The peak at 281.5 eV most likely originates from the formation of carbide-like species. We cannot exclude the possibility of aluminium carbide formation, but suggest aluminium carbide formation to be un-likely, due to a constant FWHM of the Al 2p line for the coked and uncoked sample which suggests absence of any aluminium phases other than oxide.…”
Section: The Nature Of the Sites Active In Methane Combustionmentioning
The catalytic combustion of <1 % methane in air over palladium‐based catalysts is investigated. The influence of operating parameters and pretreatment conditions on the activity and stability of the catalysts is studied. X‐ray photoelectron spectroscopy analysis of Pd/Al2O3 indicates the emergence of Pd carbide, even under lean conditions (0.6 % methane) and at temperatures as low as 180 °C. Significant differences were observed in the light‐off temperatures and extent of coke deposition, depending on whether the catalysts were conditioned under oxidizing or reducing conditions. The oxidized palladium catalysts were reduced by methane under reaction conditions and exhibited similar activity compared to catalysts which were activated under hydrogen. Time‐on‐stream experiments reveal that the stability of the Pd/Al2O3 catalyst reduced in hydrogen was only marginally improved compared to catalysts calcined in air.
“…Silicon carbide (SiC) is a promising semiconductor material for high power, high temperature, high frequency electronic devices because of its unique material properties. [1][2][3] SiC has been used to fabricate many kinds of power devices, such as high-voltage Schottky barrier diodes (SBDs), metal-semiconductor field-effect transistors (MESFETs), and photoconductive semiconductor switches (PCSSs). [4][5][6] The electrical properties of metal/SiC have an important effect on the performance of a SiC power device.…”
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