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

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_xNA), 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 N₂ 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_xNA catalyst has a larger surface area and a narrower pore size distribution than the Ni/Al₂O₃ catalyst (NA); furthermore, the M-Mg_xNA catalyst exhibits high catalytic stability under the tested conditions of 600 °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.