Catalytic steam reforming of ethanol over high surface area CeO2:: The role of CeO2 as an internal pre-reforming catalyst

In the present work, it was found that high surface area ceria (CeO2 (HSA)), synthesized by a surfactant-assisted approach, have useful ethanol steam reforming activity under solid oxide fuel cells (SOFCs) temperatures. The catalyst provides good reforming reactivity and high resistance toward carbon deposition compared to Ni/Al2O3 and conventional low surface area ceria (CeO2 (LSA)). Although the hydrogen selectivity at steady state from the ethanol steam reforming over CeO2 (HSA) was lower than Rh/Al2O3, the resistance toward carbon deposition of CeO2 (HSA) was considerably higher. At temperature 900 degrees C, the main products from the steam reforming of ethanol over CeO2 (HSA) (with inlet C2H5OH/H2O molar ratio of 1.0/ 3.0) were H-2 (with the selectivity of 67.5%), CH4, CO, and CO2. In contrast, the formations of C2H4 and C2H6 were also observed from the steam reforming of ethanol over Ni/Al2O3 and CeO2 (LSA). The combination use of CeO2 and Ni/Al2O3 was studied in an annular ceramic reactor by applying CeO2 as an internal pre-reforming catalyst. The main purpose of CeO2 is to convert all ethanol and other high hydrocarbon compounds (e.g. C2H4 and C2H6) forming CH4, CO, CO2, and H-2, while Ni/Al2O3 is applied to reform all CH4 left from the pre-reforming section and maximize the yield of hydrogen production. After operated at 900 degrees C for 100 h, this combination pattern offers high hydrogen selectivity (87.0-91.4%) and good resistance toward carbon deposition. This successful development eliminates the requirement of expensive noble metal catalysts or the installation of an external pre-reformer in order to reform ethanol internally (IIR-SOFC). (c) 2006 Elsevier B.V. All rights reserved.