This work was conducted to clarify the influence of the type of metal and support on the sulfur tolerance and carbon resistance of supported noble metal catalysts in steam reforming of liquid hydrocarbons. Al 2O 3-supported noble metal catalysts (Rh, Ru, Pt, and Pd), Rh catalysts on different supports (Al 2O 3, CeO 2, SiO 2, and MgO), and Pt catalysts supported on CeO 2 and Al 2O 3, were examined for steam reforming of a liquid hydrocarbon fuel (Norpar13 from Exxon Mobil) at 800 °C for 55 h. The results indicate that (1) Rh/Al 2O 3 shows higher sulfur tolerance than the Ru, Pt, and Pd catalysts on the same support; (2) both Al 2O 3 and CeO 2 are promising supports for Rh catalyst to process sulfur-containing hydrocarbons; and (3) Pt/CeO 2 exhibits better catalytic performance than Pt/Al 2O 3 in the reaction with sulfur. Transmission electron microscopy (TEM) results demonstrate that the metal particles in Rh/Al 2O 3 were better dispersed (mostly in 1-3 nm) compared with the other catalysts after reforming the sulfur-containing feed. As revealed by X-ray photoelectron spectroscopy (XPS), the binding energy of Rh 3d for Rh/Al 2O 3 is notably higher than that for Rh/CeO 2, implying the formation of electron-deficient Rh particles in the former. The strong sulfur tolerance of Rh/Al 2O 3 may be related to the formation of well-dispersed electron-deficient Rh particles on the Al 2O 3 support. Sulfur K-edge X-ray absorption near edge structure (XANES) spectroscopy illustrates the preferential formation of sulfonate and sulfate on Rh/Al 2O 3, which may be beneficial for improving its sulfur tolerance as their oxygen-shielded sulfur structure may hinder direct Rh-S interaction. Because of its strong sulfur tolerance, the carbon deposition on Rh/Al 2O 3 was significantly lower than that on the Al 2O 3-supported Ru, Pt, and Pd catalysts after the reaction with sulfur. The superior catalytic performance of CeO 2-supported Rh and Pt catalysts in the presence of sulfur can be ascribed mainly to the promotion effect of CeO 2 on carbon gasification, leading to much lower carbon deposition compared with that for the Rh/Al 2O 3, Rh/MgO, Rh/SiO 2, and Pt/Al 2O 3 catalysts.
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