Preparation and characterization of nanosized nickel oxide

Nanosized nickel oxide was synthesized by a simple liquid-phase process to obtain the hydroxide precursor and then calcined to form the oxide. The precursor and the nickel oxide were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), thermal analysis (TG) and temperature-programmed reduction (TPR). The results indicated that the particle size of nickel oxide was controlled by the calcined temperature (T_C). Mixed phases of nickel oxide and nickel hydroxide were present as the T_C was lower than 300 °C. Non-stoichiometric nickel oxide (NiO_x, x = 1.2) was formed between 250 °C and 400 °C and a pure nickel oxide was formed as the T_C arrived 500 °C. The particle size of nickel oxide changed as the calcined temperature was controlled under 250 °C, 300 °C, 400 °C and 500 °C, the order was 5.6 nm, 6.5 nm, 11 nm and 17 nm, respectively.