Ni catalysts with Mo promoter for methane steam reforming

NiO/Al₂O₃ catalyst precursors were prepared by simultaneous precipitation, in a Ni:Al molar ratio of 3:1, promoted with Mo oxide (0.05, 0.5, 1.0 and 2.0 wt%). The solids were characterized by adsorption of N₂, XRD, TPR, Raman spectroscopy and XPS, then activated by H₂ reduction and tested for the catalytic activity in methane steam reforming.The characterization results showed the presence of NiO and Ni₂AlO₄ in the bulk and Ni₂AlO₄ and/or Ni₂O₃ and at the surface of the samples.In the catalytic tests, high stability was observed with a reaction feed of 4:1 steam/methane. However, at a steam/methane ratio of 2:1, only the catalyst with 0.05% Mo remained stable throughout the 500 min of the test.The addition of Mo to Ni catalysts may have a synergistic effect, probably as a result of electron transfer from the molybdenum to the nickel, increasing the electron density of the catalytic site and hence the catalytic activity.