Abstract: The optimum process for preparing nanometer nickel oxide by the citrate-gel method was studied.
The gel and products derived from the consequent thermal decomposition were characterized by FTIR, XRD, SEM and BET techniques.The thermal decomposition
of the gel was analysed by TG/DTA. The effects of heat-treatment temperature, time on particle shape, size and specific surface area were studied and the
preparation process was optimized. The NiO prepared in the optimum conditions (CA: Ni²⁺ mole ratio 1.2:1.0, 400℃ heat-treatment for 1h) has
particle size <50nm, specific surface area >180m²/g. The metallic nickel formation during the gel heat treatment is due to the in situ reduction
of nickel oxide by carbon or carbon monoxide produced from the gel precursor.

Key words: citrate-gel process, nanometer nickel oxide, thermal treatment