Water effect in hydrogen production from methane

Ni/MgO and Ni/Al₂O₃ catalysts were prepared, by wet impregnation, to compare their performance in hydrogen production from methane CPO, wet-CPO and SR. The catalytic activity was tested at 1073 K, 1 bar and 600–1200 h⁻¹. Fresh and used catalysts were characterized by different techniques. Both supports, as expected, had a low surface area (27.1 m²/g MgO and 6.2 m²/g α-Al₂O₃), as determined by BET method. The images obtained with SEM and TEM revealed that the Ni was more dispersed in the MgO support than in the Al₂O₃ one. By XRD a strong interaction, as solid-solution, between NiO and MgO was found in the 30Ni/MgO and 40Ni/MgO catalysts. The fresh 40Ni/Al₂O₃ reduced catalyst was partially reduced. But after the activity tests the stability of the reduced Ni became bigger. Some Ni sintering was also observed in the 40Ni/Al₂O₃ after the wet-CPO and SR tests. The behaviour of the three catalysts was very good in CPO methane conversion (90–93%), but the gradual increase of the steam to carbon ratio, wet-CPO and SR, affected negatively the conversion.