Preparation And Catalytic Performance Of Novel Catalysts For Steam Reforming Of Methane

Methane reforming reactions are important routes for H₂ or synthesis gasproduction. Because the demand of H₂ increases and H₂ or synthesis gas is themajor feed-stock for C1 chemistry, the importance of methane reformingreactions is increasing. Ni-based catalysts are one of the good catalyst systemsfor the steam reforming of methane. However, a rapid deactivation for carbondeposition or metal loss at high temperature had been reported for nickelcatalysts. Therefore it is necessary to develop new catalysts to improve itsactivity and stability. SBA-15, which possesses larger pores, thicker walls andhigher thermal stability, may be used as a promising catalyst support. If the Nicomponent is confined into the channels of SBA-15, the sintering of the Nicomponent will be avoided and the stability of the catalyst will be improved.In this paper, a series of Ni/SBA-15, 10wt.%Ni/Ce_1-xZr_xO₂/SBA-15,Ni/SBA-15/Al₂O₃/FeCrAl and Ni/Ce_1-xZr_xO₂/SBA-15/Al₂/O₃/FeCrAl catalystswere prepared. The catalytic activity of the catalysts for the steam reformingof methane was evaluated, and the structure of the catalysts was characterizedusing XRD,BET,TPR,TEM and SEM techniques. The results of the catalytic activity indicated that, for Ni/SBA-15catalysts, the Ni content of catalyst with 10wt.% would be proper for steamreforming of methane. 10wt.%Ni/SBA-15 catalyst exhibited an excellentstability at 800℃for 740 h. For Ni/Ce_1-xZr_xO₂/SBA-15 catalysts, the CH₄conversion was higher than that of Ni/SBA-15 at range from 700-800℃. ForNi/SBA-15/Al₂O₃/FeCrAl and Ni/Ce_1-xZr_xO₂/SBA-15/Al₂O₃/FeCrAl catalysts,the catalytic activity was the same as that of the Ni/SBA-15 and Ni/Ce_1-xZr_xO₂/SBA-15, and they can be operated at the higher space velocity condition.The results of the structural characterization of the catalysts indicated thatthe hexagonal regularity mesoporous structure of SBA-15 was maintainedafter Ni was introduced into SBA-15 mesoporous. The nickel species had beenconfined into SBA-15 mesoporous. For Ni/Ce_1-xZr_xO₂/SBA-15 catalysts,Ce_1-xZr_xO₂ can promote dispersion of the nickel species; change the chemicalenvironment of nickel species, and moderate reducibility of the activitycomponent. Consequently, catalytic activity was improved. For Ni/SBA-15/Al₂O₃/FeCrAl and Ni/Ce_1-xZr_xO₂/SBA-15/Al₂O₃/FeCrAl catalysts, after heattreatment, the segregation ofα-A₂O₃ layer on the FeCrAl surface waspresented. The formation of the washcoat layers improved the combinationability between the activity component and the FeCrAl support.