Three-dimensional macro/mesoporous tricobalt tetraoxide Co3O4 was prepared via a facile self-sustained decomposition using the complexes of metallic salts and organics (metal-organic complexes). Porous Co3O4 material was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectrum (XPS) to examine the morphology and microstructure to find out the cause. Co3O4 with the 3D hierarchical porous structure consisting of nanoparticles has a coral-like shape with a size of tens of micrometers and exhibits the hierarchically porous morphology, in which the walls of the macropores contain smaller mesopores. The catalytic performance of the porous Co3O4 for CO oxidation has been studied with a continuous flow fixed-bed quartz microreactor. The porous Co3O4 exhibits excellent catalytic activity for CO oxidation, the CO conversion rate reaches 100% at 140 degrees C. (C) 2014 Elsevier B.V. All rights reserved.