Abstract: Non-supported nickel oxide catalyst samples were prepared by precipitation using different nickel precursors. The influence of nickel precursors on catalyst behavior was investigated by X-ray diffraction, H₂ temperature-programmed reduction, CH₄ temperature-programmed surface reaction, and methane decomposition stability tests. The results showed that the particle size of the NiO sample prepared from a nickel acetate precursor (named NiO-A) was smaller than that of the NiO sample prepared from nickel nitrate (NiO-N). NiO-A could be reduced more easily than NiO-N, and the activity of the reduced NiO-A sample (Ni-A) for methane decomposition was higher than that of the reduced NiO-N sample (Ni-N). The complexation of nickel acetate with glycol was the key factor leading to the smaller NiO particles. The results of the catalytic stability tests showed that the Ni-A catalyst exhibited higher stability than the Ni-N catalyst.

Key words: nickel nitrate, nickel acetate, nickel oxide, non-supported catalyst, methane, decomposition