Nickel-based catalysts supported on zirconia (Ni/ZrO2) were prepared, characterized and tested for the production of hydrogen via steam reforming of bio-oil. The effects of metal loading on the hydrogen (H-2) and carbon monoxide (CO) yields and the carbon deposition percentage were investigated. In order to examine the effect of support, the results obtained on zirconia support were compared to the results obtained over nickel-based catalysts supported on alumina (Ni/Al2O3). It was found that the Ni/ZrO2 catalysts presented higher activity than those supported on alumina for hydrogen production. The CO yields obtained over Ni/ZrO2 catalysts were also higher than those obtained over Ni/Al2O3 catalysts. A potential H-2 yield of almost 80% can be obtained at 850 degrees C using Ni/ZrO2 catalysts with a nickel content of 14%; whereas, the H-2 yield was less when Ni/Al2O3 catalysts were employed. The amount of carbon deposited on each catalyst was measured. It was observed that the carbon depositions on the Ni/ZrO2 catalysts were extremely high. A comparison between the amounts of carbon deposited on the Ni/Al2O3 and Ni/ZrO2 catalysts revealed that the carbon deposition is strongly dependent on the type of support. (C) 2011 Elsevier B.V. All rights reserved.