In this communication, we demonstrate the development of nickel oxide nanosheets array on carbon cloth (NiO NA/CC) as an integrated three-dimensional oxygen-evolving electrode. The electrode exhibits high catalytic activity with an onset overpotential of 295 mV and a Tafel slope of 116 mV/dec. It needs an overpotential of 422 mV to drive current density of 10 mA/cm(2) and maintains its catalytic activity for at least 10 h. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.