Cobalt oxide nano-particles were prepared by combustion method using urea as a combustion fuel. The effects of calcination temperature, 350-1000 degrees C, on the physicochemical, surface and catalytic properties of the prepared Co3O4 nano-particles were studied. The products were characterized by thermal analyses (TGA & DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Textural features of the obtained catalysts were investigated using nitrogen adsorption at -196 degrees C. X-ray diffraction confirmed that the resulting oxide was pure single-crystalline Co3O4 nano-particles. Transmission electron microscopy indicating that, the crystallite size of Co3O4 nano-crystals was in the range of 8-34 nm. The catalytic activities of prepared nano-crystalline Co3O4 catalysts were tested for H2O2 decomposition at 35-50 degrees C temperature range. Experimental results revealed that, the catalytic decomposition of H2O2 decreases with increasing the calcination temperature. This was correlated with the observed particle size increase accompanying the calcination temperature rise. (C) 2013 Elsevier B.V. All rights reserved.