2D CdS/Ni-Fe LDH (short for layered double hydroxide) heterostructures were designed and fabricated by following a facile in-situ growth method. The CdS nanoparticles are well dispersed on the surface of Ni-Fe LDH to form nanoscale heterojunctions, as suggested from the TEM and elemental mapping images. The composites with optimum CdS amount (15 wt%) take on notably higher hydrogen evolution activity (469 mu mol h(-1) g(-1)) than the independent CdS and Ni Fe LDH from aqueous methanol solution under xenon lamp irradiation. The nano-heterojunction notably promotes the H-2 evolution kinetics and greatly suppresses the recombination of photo-induced electrons and holes, which is responsible for the enhanced photocatalytic activity of the composites, as demonstrated by the reducing onset potential and increasing photocurrent of the composites in the photoelectrochemical experiments. The possible photocatalytic mechanism is proposed on the basis of the defined position of energy band edges. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.