Carbon fiber cloth supported micro- and nano-structured Co electrode is prepared by a facile and fast square-wave electrodeposition method. The electrode is characterized by scanning electron microscope and X-ray diffractometer. Its electrocatalytic performance for hydrazine oxidation in alkaline media is investigated by means of cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Co is uniformly deposited on the carbon fiber surface and presents as nano-sheets and micro-particles intersected mutually. The nano-sheets have a thickness of around 250 nm and the size of the micro-particles is up to around 10 mu m. Hydrazine electrooxidation on the electrode occurs via both direct and indirect pathways. The activation energy of the direct electrooxidation of hydrazine is 16.6 kJ mol(-1) which is higher than that of the electrooxidation of hydrogen in the indirect pathway (9.9 kJ mol(-1)). (C) 2013 Elsevier Ltd. All rights reserved.