In this paper, we report the use of Zn0.76Co0.24S/CoS2 nanowires array on Ti mesh (Zn-Co-S/TM) topotactically derived from ZnCo2O4 nanowires array precursor as a durable and efficient bifunctional hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalyst in strongly alkaline media. This Zn-Co-S/TM electrode drives 20 mA cm (2) at 238 mV HER overpotential and 20 mA cm (2) at 330 mV OER overpotential. The corresponding two-electrode alkaline water-splitting system achieves 10 mA cm (2) at a cell voltage of 1.66 V. (C) 2015 Elsevier Ltd. All rights reserved.