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 N-2, XRD, TPR, Raman spectroscopy and XPS, then activated by H-2 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. (C) 2009 Elsevier Ltd. All rights reserved.