The increasing demand for energy and strain on the environment due to human activities has led to an increased focus on the development of cleaner alternative fuels. Hydrogen gas is found as a substitute in the progress of sustainable energy sources due to its high calorific values and clean combustion products. In this work molybdenum disulfide (MoS2) decorated on graphitic carbon nitride (g-C3N4) was synthesized via a simple hydrothermal route. The morphology and surface structure of MoS2/g-C3N4 were analyzed by SEM, TEM, and EDS techniques. The crystal structure, optical properties, and elemental composition of the catalyst were investigated by PXRD, UVevis, RAMAN, and XPS. BET analysis is carried out to determine the surface area of both MoS2 and MoS2/g-C3N4. The catalyst material, MoS2/g-C3N4 demonstrates enormous improvement in production of H-2 with low onset potentials (similar to 0.24 V vs. RHE), small Tafel slop (63 mV/dec), and excellent cycling stability as compared with bare MoS2. The enhanced electrochemical performance of the MoS2/g-C3N4 heterostructure could be attributed to higher charge carrier mobility in heterostructure interface, improved specific activity and large surface area. The focus of this study is to construct a new MoS2 based semiconductor heterostructure electrocatalyst with improved HER activity. (C) 2017 Elsevier Ltd. All rights reserved.