The water gas shift reaction (WGSR) is the main route to produce hydrogen for industrial applications. At high temperatures (320-450 degrees C), the reaction is carried out over hematite-based catalysts doped with chromium. This solid has several advantages but deactivates with time due to the decrease of specific surface area. Therefore, there is a need of developing more efficient catalysts. Zirconia-supported platinum emerges as an attractive catalyst, with the advantage of being non-toxic. In order to optimize these solids the effect of cerium on the properties of zirconia-supported platinum catalysts was studied in this work. Samples were prepared by impregnation techniques and characterized by ICP/ OES, X-ray diffraction, specific surface area and temperature programmed reduction. Monoclinic and tetragonal phases were found in the zirconia-based samples. Cerium stabilized the microcrystals of the tetragonal phase and then increased the specific surface area. Besides, it increased the activity of the catalyst. This catalyst was more active than a hematite-based commercial one and thus is an attractive option to water gas shift reaction. (c) 2005 Elsevier B.V. All rights reserved.