NiCo2O4 nanoflakes, NiCo2O4 nanoflakes supported on carbon black (NiCo2O4/C) and titanium suboxide (NiCo2O4/Ti4O7), respectively, are synthesized by a simple solution method followed by an annealing process. Their electrocatalytic performance for oxygen evolution reaction (OER) is investigated. The results show that the NiCo2O4/Ti4O7 possesses not only the best stability but also the highest catalytic activity, which may be attributed to the enhanced electrical conductivity and higher contents of Co2+ and Ni3+ caused by Ti4O7 according to the analyses for electrochemical impedance spectra and X-ray photoelectron spectra. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.