The effect of hydrogen pressure on the reduction kinetics of nickel oxide was investigated by thermogravimetry at temperatures of 300, 350 and 400°C. Pore-diffusion resistance to the reduction was minimized by the use of thin, dense, flat specimens (12 mm × 12 mm × 54 µm) of NiO(s). The partial pressure of H2 in the helium-hydrogen gas mixtures was varied from 0.109 to 1.0 atm (11 044 to 101 325 Pa) in each of the three sets of isothermal experiments. The reduction of nickel oxide appears to be first-order with respect to the H2 pressure.
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