A novel cobalt decorated activated carbon (AC) air cathode with facilitated oxygen reduction activity is developed for microbial fuel cells (MFCs). Two kinds of cobalt modified cathodes Co(OH)(2)/AC and Co3O4/AC were prepared via a simple electrodeposition. The electrodeposition process was optimized to achieve high a surface area and pore volume structure. Transmission electron spectroscopy (TEM) analyses confirmed that Co3O4 and Co(OH)(2) nanosheets were homogeneously distributed on the AC. Compared to raw AC. Electrochemical evaluation showed that the onset potentials towards oxygen reduction reaction (ORR) of Co(OH)(2)/AC and Co3O4/AC shifted to higher potential and the exchange current densities were increased by 2.6 times and 1.6 times, respectively. The MFCs with Co3O4/AC reached a maximum power density of 1420.8 +/- 54 mWm(-2), significantly improved performance by 64% in relative raw AC. (C) 2016 Elsevier Ltd. All rights reserved.