A facile synthesis approach to fabricate Cu-doped MoS2/Bi2S3 (Cu-MoS2/Bi2S3) photo catalysts is reported. The photocatalyst samples with varying amounts of Cu are applied in the photocatalytic splitting of water to produce H-2 under the irradiation of simulated solar light. The Cu-MoS2/Bi2S3 photocatalysts with an optimum Cu loading of 20 mol% exhibited high photocatalytic performance, achieving a total H-2 yield of 32.4 mol/h after 6 h of reaction. The photoactivity of the Cu-doped sample was shown to have risen more than 40% than that of pure MoS2/Bi2S3. The improved performance is attributed to the impurity states generated within Cu-doped MoS2, which serve as trapping sites for photogenerated electrons. The effective charge transfer mechanism achieved was evidenced by photo electrochemical measurements. Based on the experimental results obtained, a plausible mechanism for the photocatalytic process associated with Cu-MoS2/Bi2S3 was proposed. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.