In this work, a series of highly efficient and noble metal-free Co0.2Cd0.8S/g-C3N4 nano composites were synthesized via a facile one-step hydrothermal strategy. The Co0.2Cd0.8S/g-C3N4 composites modified with 10 wt% g-C3N4 (CCNE10) exhibited the highest photo catalytic hydrogen evolution rate, which was 1.85-times as high as that of pure Co0.2Cd0.8S and 7.85-times higher than CdS. Furthermore, the CCNE10 catalyst was very stable in cycling hydrogen production, which is ascribed to the unique g-C3N4-modified CdS CoS structure with fast photogenerated electron transport character. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.