Hydrogen production from steam reforming of hydrocarbons over alkaline-earth metal-modified Fe- or Ni-based catalysts

The steam reforming of isooctane and methylcyclohexane (MCH) was investigated over Fe and Ni-based catalysts. FeMg/Al2O3 catalyst, effective for CH4 decomposition in the presence of O-2/CO2, was active for steam reforming of isooctane, being a little easier to cause C-C bond cleavage than MCH, but the rate of hydrogen production was insufficient, although the rate was only slightly improved by Rh modification, due to raised formation of CH4 and C2. FeMg/Al2O3 catalyst was also less active for the steam reforming of MCH than Ni systems. Modification of FeMg/Al2O3 catalyst with rhodium resulted in the increased formation of aromatic byproducts. The rate of H-2 production with Ni/ZrO2 catalyst was found to be 7 times higher than that with FeMg/Al2O3 Furthermore, the stability of the Ni/ZrO2 catalyst was found to be improved by the addition of alkaline-earth metals into the catalyst (M/Ni = 1:2 wt ratio). In particular, the addition of Sr was the most effective and the activity of NiSr/ZrO2 catalyst for the reaction at 973 K remained stable after 100 hours, although below 10% decrease in the rate of H-2 formation was observed. On the contrary, above 50% decrease in the rate was observed over Ni/ZrO2 catalyst, after 100 hours. This Sr effect, possibly, could be associated with the formation of mixed oxides consisting of Sr and Zr (or Ni). The NiSr/ZrO2 catalyst was also effective for the steam reforming of model gasoline, which contained organic mixtures with different reforming reactivities such as naphthenes, aromatics, and n- and iso-paraffins.