Applied Catalysis B: Environmental, Vol.48, No.4, 243-248, 2004
Control of the product ratio of CO2/(CO+CO2) and inhibition of catalyst deactivation for steam reforming of gasoline to produce hydrogen
Factors control ling the product ratio of CO2/(CO+CO2) and methods for inhibiting deactivation of catalyst for steam reforming of gasoline were studied. Syngas(H-2+CO) as major product was produced on Ni-Mo/Al2O3 and the major product on Ni-Re/Al2O3 was H-2 and CO2 at the same reaction conditions. Hydrogen with a high CO2 / (CO + CO2) ratio of about 92% was produced by coupling reaction of steam reforming and water gas shift on Ni-Re/Al2O3 catalyst at 805 K. The multifunctional activity of the bimetallic catalyst of Ni-Re/Al2O3 and the suitable reaction temperature were of crucial significance for the coupling reaction. Although no deactivation could be observed on both Ni-Mo/Al2O3 and Ni-Re/Al2O3 catalysts for steam reforming of sulfur-free fuels in about 200h of time on stream, the activity and sulfur-tolerance of Ni-Re/Al2O3 was much better than the values of Ni-Mo/Al2O3 for steam reforming of sulfur-containing fuels because of the unique role of rhenium in the Ni-Re catalyst. The unique role of rhenium in Ni-Re catalyst was mainly because of alloying of rhenium with nickel to form bimetallic Ni-Re sites and interaction of rhenium with sulfur to form S-Re binds. The sulfur-tolerance of Ni-Re/Al2O3 for steam reforming of sulfur-containing gasoline was improved further by addition of a small amount of ZSM-5. The activity and sulfur-tolerance of Ni-Mo/Al2O3 was also enhanced by the addition of ZSM-5. (C) 2003 Elsevier B.V. All rights reserved.
Keywords:steam reforming;coupling reaction;hybrid catalyst;catalyst deactivation;sulfur-tolerant catalyst