Oxidative steam reforming of ethanol at low oxygen to ethanol ratios was investigated over nickel catalysts on Al 2 O 3 supports that were either unpromoted or promoted with CeO 2 , ZrO 2 and CeO 2 –ZrO 2 . The promoted catalysts showed greater activity and a higher hydrogen yield than the unpromoted catalyst. The characterization of the Ni-based catalysts promoted with CeO 2 and/or ZrO 2 showed that the variations induced in the Al 2 O 3 by the addition of CeO 2 and/or ZrO 2 alter the catalyst's properties by enhancing Ni dispersion and reducing Ni particle size. The promoters, especially CeO 2 –ZrO 2 , improved catalytic activity by increasing the H 2 yield and the CO 2 /CO and the H 2 /CO values while decreasing coke formation. This results from the addition of ZrO 2 into CeO 2 . This promoter highlights the advantages of oxygen storage capacity and of mobile oxygen vacancies that increase the number of surface oxygen species. The addition of oxygen facilitates the reaction by regenerating the surface oxygenation of the promoters and by oxidizing surface carbon species and carbon-containing products.