Synthesis and thermogravimetric analysis of non-stoichiometric nickel oxide compounds

Non-stoichiometric nickel oxide was synthesized by the thermal decomposition method at different sintering temperatures upto 1100 °C. The samples were analyzed by thermogravimetric analysis (TGA). Wherein, the stoichiometry of the sample was analyzed by calculating the excess oxygen. It was found that as the sintering temperature of the precursor increases the excess oxygen present in the sample decreases, and at temperature above 700 °C, the sample becomes stoichiometric. These results were interpreted as the decomposition temperature increases, which heals the defects present in the non-stoichiometric nickel oxide. Thus, highly defective nickel oxide at lower decomposition temperature approaches stoichiometric nickel oxide as the temperature is increases above 700 °C.