An alumina (AA)/nickel (Ni) nanoparticles (NPs)-dispersed carbon nanofiber (CNF)-based electrode was for the first time used in a mediatorless double-chambered microbial fuel cell (MFC) for the simultaneous electrochemical reduction of hexavalent chromium (Cr(VI)) in water and generation of bioelectricity. Whereas the AA NPs increased the electrical conductivity of the electrode, the Ni NPs served as the catalyst for growing the CNFs on an activated carbon microfiber substrate by chemical vapor deposition and for catalyzing the Cr(VI) reduction at the cathode. Such MFCs showed a complete removal of Cr(VI) at 100 ppm-concentration, achieving a significantly high reduction rate of similar to 2.13 g/m(3)-h, besides generating electricity with the maximum power density of similar to 1540 mW/m(2), open circuit potential of 900 mV and cathodic columbic efficiency of 93%. The MFCs using the inexpensive transition metals-dispersed CNF electrode, prepared in this study, has the potential for the efficient treatment of the similar electron acceptor metals-laden wastewater, with the simultaneous generation of electricity. (C) 2016 Elsevier B.V. All rights reserved.