Methane autothermal reforming on nickel–ceria–zirconia based catalysts

Nickel catalysts supported on Ce0.5Zr0.5O2, CeO2/Al2O3, Ce0.5Zr0.5O2/Al2O3, and Al2O3 were investigated for methane autothermal reforming. Samples were characterized by BET area, X-ray diffraction, H2 temperature programmed reduction and temperature programmed desorption of CO2. Nickel dispersion was evaluated using a model reaction, the dehydrogenation of cyclohexane. Light-off experiments showed that methane autothermal reforming occurred in two steps, by an indirect mechanism: total combustion at lower temperatures followed by methane reforming by CO2 or steam at higher temperatures. Most catalysts exhibited good activity, stability, and a H2/CO ratio around 2.7 during stability tests that lasted 24 h. 10% Ni/Ce0.5Zr0.5O2/Al2O3 showed the best activity and its performance could be explained by its higher reducibility and Ni dispersion.