Studies on the steam CO2 reforming of methane over ordered mesoporous nickel-magnesium-alumina catalysts

초록

Ordered mesoporous materials have received much attention because of their high surface area and ordered pore structure. The Mg-promoted ordered mesoporous nickel-alumina catalysts (M-Mg (x) NA), which were prepared using the evaporation induced self-assembly method, were investigated in the Steam CO2 Reforming (SCR) of methane. The fresh and spent catalysts were characterized by various analytical techniques such as N-2 physisorption, small-angle X-ray scattering, X-ray diffraction, temperature-programmed reduction, thermogravimetric analysis, transmission electron microscopy and CO2-temperature programmed desorption analysis. We have found that the M-Mg (x) NA catalyst has a larger surface area and a narrower pore size distribution than the Ni/Al2O3 catalyst (NA); furthermore, the M-Mg (x) NA catalyst exhibits high catalytic stability under the tested conditions of 600 A degrees C, 1 bar and feed molar ratio of CH4:CO2:H2O = 1:1:1. We consider that the ordered mesoporosity prevents the nickel particles from sintering because of the confinement effect and decreases the particle size in the SCR reaction. Thus, the Mg-promoted ordered mesoporous nickel-alumina catalyst shows enhanced resistance to carbon formation during the steam CO2 reforming of methane.

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