Abstract: Ni/CeO₂/Al₂O₃ catalyst samples with different Ni contents were prepared by co-impregnating boehmite with aqueous solution of cerium and nickel nitrates and characterized by X-ray diffraction, N₂ adsorption, and temperature-programmed reduction. It was found that there was a strong interaction between Ni and CeO₂ species. Addition of CeO₂ promoted the reduction of NiAl₂O₄ to metal Ni, while nickel species in turn promoted the reduction of CeO₂ and reacted with Al₂O₃ to CeAlO₃. The pre-reforming of commercial liquefied petroleum gas (LPG) was investigated over Ni/CeO₂/Al₂O₃ catalyst at low steam/carbon molar ratios (less than 1.0). The effects of Ni content, reaction temperature, and S/C molar ratio on the performance of the Ni/CeO₂/Al₂O₃ catalyst were discussed. The results showed that the catalyst was highly active and stable for the steam reforming of LPG at 275–375 °C. Higher Ni content and S/C ratio promoted the steam reforming of LPG and substantially accelerated the methanation of CO_x and H₂. The stability tests indicated that the Ni/CeO₂/Al₂O₃ catalyst exhibited excellent stability and resistance to carbon deposition. The reaction mechanism for pre-reforming of higher hydrocarbons under lower S/C molar ratios was proposed.

Key words: nickel, ceria, alumina, liquefied petroleum gas, pre-reforming, steam/carbon molar ratio