Influence of preparation method on the properties and catalytic performance of Ni/La₂O₃/Al₂O₃ catalyst for dry reforming of methane

Ni/La₂O₃/Al₂O₃ catalysts were prepared by the methods of incipient wetness impregnation and evaporation. The influence of preparation method on the physicochemical properties and catalytic performance for the dry reforming of methane was investigated. The catalysts were characterized by X-ray diffraction (XRD), temperatureprogrammed reduction (H₂-TPR), BET surface area, transmission electron microscopy (TEM), and thermogravimetry and differential scanning calorimetry (TG-DSC). The catalyst prepared by incipient wetness impregnation exhibited better Ni dispersion, more symmetrical distribution of particle diameter, larger specific surface area and more rational pore structure than that prepared by evaporation. As a result, the catalyst prepared by the incipient wetness impregnation possessed better resistance to Ni sintering and coking; its average coking rate was about 0.6737 mg/(g_cat·h), only equivalent to 21% of the value of the catalyst prepared by evaporation. Moreover, the catalysts prepared by wetness impregnation exhibited much higher conversions of CH₄ and CO₂, higher selectivities of H₂ and CO, as well as better stability for methane dry reforming than the catalyst prepared by evaporation.