Hydrogen generation through electrochemical water decomposition is a promising method to address the global energy crisis. Herein, we report the synthesis of a series of flower-like Mo3S4/Co1-xS composites on Co foil (Mo3S4/Co1-xS@CF) as high-performance electrochemical water-splitting catalysts in an alkaline environment. The flower-like array structure of Mo3S4/Co1-xS@CF not only increases the electrochemically active surface area of the catalyst, but also facilitates the release of bubbles generated, resulting in enhanced catalytic activity. For the hydrogen evolution reaction, the Mo3S4/Co1-xS@CF electrode exhibits good stability and excellent catalytic activity in 1.0 M KOH (eta(10) = 105 mV), 1.0 M PBS (eta(10) = 92 mV) and 0.5 M H2SO4 (eta(10) = 68 mV) solutions. For the oxygen evolution reaction, the electrode displays excellent stability and catalytic activity in 1.0 M KOH solution (eta(10) = 215 mV). When used for overall water splitting in 1.0 M KOH solution, Mo3S4/Co1-xS@CF achieves a current density of 10 mA cm(-2) at a low potential of 1.58 V and maintains it stably for 40 h. This study presents a simple method for preparing transition metal-based bimetallic composite catalysts for efficient hydrogen production. (c) 2020 Elsevier Inc. All rights reserved.