Interplay of anions and ligands on the nature and reducibility of NiOx/Al2O3 catalysts prepared by impregnation

When NiOx/Al2O3 catalysts (Ni wt% = 1.5) are prepared by impregnation using [NiL2(H2O)2]X2 as precursors (L = diamine, X = Cl- or NO3-), a supported oxidic or metallic phase can be selectively obtained after thermal treatment in N2 depending on the nature of the ligand and counter anion; the oxidic phase can be reduced at a lower temperature than the classical nickel aluminate phase obtained from [Ni-(H2O)6](NO3)2.