A facile, one-pot, solvothermal synthesis of MoS2 microflowers (S1) and the heterostructures MoS2/g-C3N4 with varying ratios of 1:1 (S2), 1:2 (S3) and 1:3 (S4) exhibiting enhanced visible-light-assisted H-2 generation by water splitting has been reported. The compounds were thoroughly characterized by PXRD, FESEM, HRTEM, EDS, UV-vis and XPS techniques. FESEM and HRTEM analyses showed the presence of microflowers composed of nano-sized petals in case of pure MoS2 (Si), while the MoS2 microflowers covered with gC(3)N(4) nanosheets in case of MoS2/g-C3N4 heterostructure, S4. XPS analysis of S2 showed the presence of 2H phase of MoS2 with g-C3N4. The Eosin-Y/dye-sensitized visible-lightassisted photocatalytic investigation of the samples in the absence of any noble metal cocatalyst revealed very good water splitting activity of MoS2/g-C3N4 heterostructure, S2 with hydrogen generation rate of 1787 mu mol h(-1) g(-1) which is about 6 and 40 times higher than pure MoS2 and g-C3N4 respectively. The relatively higher catalytic activity of the heterostructure, S2 has been ascribed to the efficient spatial separation of photo-induced charge carriers owing to the synergistic interaction between MoS2 and g-C3N4. A possible mechanism for the Eosin-Y-sensitized photocatalytic H-2 generation activity of MoS2/g-C3N4 heterostructures has also been presented. The enhanced activity of S2 was further supported by fluorescence measurements. Thus, the present study highlights the importance of non-noble metal based MoS2/g-C3N4 heterojunction photocatalysts for efficient visible-light-driven H-2 production from water splitting. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.