Partial oxidation of methane over Ni/Mg-Al oxide catalysts prepared by solid phase crystallization method from Mg-Al hydrotalcite-like precursors

Abstract

Ni-supported catalyst was prepared by the solid phase crystallization (spc) method starting from Mg-Al hydrotalcite (HT) anionic clay as the precursor; it was tested for the partial oxidation of CH 4 to synthesis gas. The precursor based on [Mg 6Al 2(OH) 16CO 3 2−]·4H 2O was prepared by co-precipitation method from nitrates of the metal components. The precursor was then thermally decomposed and reduced to form Ni-supported catalyst (spc-Ni/Mg-Al). Ni 2+ can well occupy the Mg 2+ sites in the hydrotalcite resulting in the formation of highly dispersed Ni metal particles on spc-Ni/Mg-Al. The spc-Ni/Mg-Al thus prepared, showed high activity and selectivity to synthesis gas even at high space velocity. When Ni was supported by impregnating Mg-Al mixed oxide prepared from Mg-Al HT, the activity of imp-Ni/Mg-Al was higher than those of Ni/α-Al 2O 3 and Ni/MgO while it was close to that of spc-Ni/Mg-Al. The relatively high activity of the imp-Ni/Mg-Al may be due to the regeneration of Mg-Al HT phase from the mixed oxide during the preparation resulting in incorporation of Ni 2+ on the Mg 2+ sites in the HT as seen in the spc method.