The present work tentatively investigated the effect of cobalt precursors (cobalt acetate and cobalt nitrate) on the physicochemical properties of CoOx/gamma-Al2O3 catalysts calcined in N-2. XRD, Raman, XPS, FTIR, and UV-vis DRS results suggested that CoO/gamma-Al2O3 was obtained from cobalt acetate precursors and CoO was dispersed on gamma-Al2O3 below its dispersion capacity of 1.50 mmol/(100 m(2) gamma-Al2O3), whereas Co3O4/gamma-Al2O3 was obtained from cobalt nitrate precursors and Co3O4 preferred to agglomerate above the dispersion capacity of 0.15 mmol/(100 m(2) gamma-Al2O3). Compared with Co3O4/gamma-Al2O3, CoO/gamma-Al2O3 catalysts were difficult to be reduced and easy to desorb oxygen species at low temperatures and presented high activities for CO oxidation as proved by H-2-TPR, O-2-TPD, and CO oxidation model reaction results. A surface incorporation model was proposed to explain the dispersion and reduction properties of CoO/gamma-Al2O3 catalysts. Crown Copyright (C) 2010 Published by Elsevier Inc. All rights reserved.