Magnesium nickel mixed oxides prepared from thermal decomposition of citratonickel (II) precusor

Abstract

Nickel-based oxides are catalysts used in the partial oxidation, carbon dioxide reforming of methane and fabrication of carbon nanotubes by thermal decomposition of methane. Complexes Mg-2 [Ni(Hcit)(2)] (.) 10H(2)O and Mg[Ni(Hcit) (H2O) (2)](2) (.) 8H(2)O (H(4)cit = citric acid) are prepared from the reaction of MgCl2 with the complexes (NH4) (4)[Ni(Hcit) (2)] (.) 2H(2)O and (NH4) (2)[Ni(Hcit) (H2O)(2)](2) (.) 2H(2)O respectively. The complexes are decomposed to obtain nickel-based oxides Mg2NiO3 and MgNi2O3. XRD patterns of these new phases are close to the pure phases of MgO and NiO, but the dimensions of the lattice parameters of these new phases are between them. This indicates that the solid-solution is formed due to a very good mutual solubility between MgO and NiO. It is deduced that the preparation of mixed oxides by citrate method is:related closely with the decomposition of well-characterized citrate nickel (II) complexes.