Rational design of Mg-Al mixed oxide-supported bimetallic catalysts for dry reforming of methane

A novel synthetic strategy for preparing bimetallic Ru-M (M = Cr, Fe, Co, Ni and Cu) catalysts, supported on Mg-Al mixed oxide, has been introduced. It was based on a “memory effect”, i.e. on the ability of Mg-Al mixed oxide to reconstruct a layered structure upon rehydration with an aqueous solution. By repeated calcinations-rehydration cycles, layered double hydroxide (LDH) precursors of catalysts containing two different metals were synthesized. Bimetallic catalysts were then generated (i) in situ from LDH under methane reforming reaction conditions and (ii) from mixed metal oxides obtained by preliminary LDH calcination. Among all the LDH-derived catalysts, a Ru0.1%-Ni5.0%/MgAlOx sample revealed the highest activity and selectivity to syngas, a suitable durability and a low coking capacity. A promoting effect of ruthenium on catalytic function of supported nickel was demonstrated. Preliminary LDH calcination was shown to markedly affect the catalytic activity of the derived catalysts and especially their coking properties.