A series of Ni–Ce catalysts supported on illite clay containing different cerium loading were tested with respect to autothermal reforming of methane at 800 °C using a GHSV = 60,000 mL g⁻¹ h⁻¹. The addition of oxygen in the gaseous reactant feed, under the used experimental condition was found to play a key role since the carbon balance is significantly higher as compared to CH₄/CO₂ mixture.

The addition of cerium was found to enhance the specific surface area as result of meso-porosity development. Furthermore, the nickel particles become smaller in the presence of Ce, decreasing the Ni° average size from 34.2 for 10Ni to 16.3 nm for 10Ni15Ce. The best catalytic activity and stability were obtained on the catalyst containing 15 wt.% of cerium, apparently attributed to its redox properties and further improvement on the nickel dispersion. It should be pointed out that the observed catalytic performance was high even after 24 h under reaction stream.