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 MoO4-2 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.