Particle sizes, shapes and porosities are largely determined by various synthesis techniques but it is suggested that precursor material may also strongly influence these properties.

Catalytic materials are most effective when synthesised as spherical particles and among the numerous methods suggested for synthesizing spherical particles, the sol-gel method is currently the most promising.

The Sol-Gel method was used by Thai researchers Chatchawan Sookman and Paisan Kongkachuiychay from Kasetsart University. Different nickel precursors and bases yielded NiO particles with differing particle sizes.

In all, six different systems were studied. NiO particles from Ni(NO3)2 were the largest followed by NiO from NiCl2 and NiSO4 respectively. In addition, use of NaOH yielded slightly larger NiO particles compared to when KOH was used as a precursor. Furthermore, the NiO crystal size was found to increase with an increase in the calcination temperature and concentration of nickel salts.

The researchers found Ni(NO3)2 and NaOH were the most appropriate reactants for synthesis of nickel oxide due to the properties of the precursors.

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Kasetsart University