Nitrogen-doped carbon nanotubes (NCNTs) immobilized cobaltic sulfide (Co3S4/NCNTs) was prepared by the first formation of Co(OH)(2)/NCNTs and the subsequent anion-exchange of S2- with OH-, accompanied with the partial oxidation of Co2+. The morphology and microstructure of the prepared Co3S4/NCNTs nanocomposite were characterized by TEM, SEM, XRD and XPS. The electrochemical properties of Co3S4/NCNTs nanocomposite for oxygen evolution reaction (OER) were evaluated by polarization curves and cyclic voltammetry (CV). The results show that Co3S4/NCNTs composite exhibits excellent performance for OER with potential of 0.65 V vs. SCE, corresponding to over-potential of 0.43 V at the current of 10 mA cm(-2) in 0.1 M KOH electrolyte, being a promising OER electrocatalyst. (C) 2014 Elsevier B.V. All rights reserved.