Three different Co3O4 materials in sphere, cube and truncated cube were prepared by a hydrothermal process and tested in catalytic phenol degradation using oxon (R). The properties of the Co3O4 were characterized by several techniques such as X-ray diffraction (XRD), N-2 adsorption, and scanning electron microscopy (SEM). Co3O4-cube is highly effective in heterogeneous activation of oxon (R) to produce sulfate radicals for phenol degradation and the activity of catalysts shows an order of Co3O4-cube > Co3O4-sphere > Co3O4-truncated cube. Kinetic study showed that phenol degradation followed a first order reaction. (C) 2017 Elsevier B.V. All rights reserved.