Microbial electrolysis cells (MECs) are generally regarded as a promising future technology for manufacturing green hydrogen from organic material present in wastewaters and other renewable energy sources. However, the development of inexpensive and high-efficient cathode catalyst is the most critical challenge for MECs to become a commercialized H-2 production technology. In this study, a non-noble metal electroformed Ni mesh cathode alternatives to typical cathode material (Pt/CC) was intensively examined in a single-chamber membrane-free MEC. To the best of our knowledge, the use of electroformed Ni mesh as the MEC cathode catalyst has not been reported so far. The MEC was operated in fed-batch mode and the performance of the Ni mesh cathode was compared with that of Pt/CC cathode in terms of columbic efficiencies (75 +/- 4% vs. 72.7 +/- 1%), overall hydrogen recovery (89.3 +/- 4% vs. 90.9 +/- 3%), overall energy efficiency (62.9 +/- 5% vs. 69.1 +/- 2%), the maximum volumetric hydrogen production rate (4.18 +/- 1 m(3) H-2/m(3) d vs. 4.25 +/- 1 m(3) H-2/m(3) d), volumetric current density (312 +/- 9 A/m(3) vs. 314 +/- 5 A/m(3)). The obtained results in this study highlight the great potential of using the electroformed Ni mesh catalysts as a viable cathode material for hydrogen production in MECs. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.