In this work, graphene(GP) supported Co-Mo-P catalysts for H-2 generation were prepared via an in -situ synthesis strategy with the help of photogenerated electrons. The transmission electron microscopy images (TEM) of the catalysts indicated that the elements of Co, Mo and P were distributed in a relatively homogeneous manner in the catalysts. The Co-Mo-P/GP catalyst exhibited high photocatalytic activity for hydrogen generation sensitized by Eosin Y (EY) under visible light. The Mo/(Co + Mo) molar ratio (chi(Mo)) was varied in the catalyst to study the effect of Mo doping on the catalytic efficiency. The highest rate of the H-2 generation was found to be as high as 33.3 mmol.h(-1).gCo(-1) when the chi(Mo) was 10%. The apparent quantum efficiency (AQE) of the reaction over the Mo doped catalyst under 430 nm irradiation was 52.6%, which was six times higher than that using the un-doped Co-P/GO catalyst. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.