Although black phosphorous (BP) and its derived materials have shown great potential for application in photocatalytic H-2 evolution reaction (HER), their HER activity and stability still remains unsatisfied mainly due to the insufficient charge separation, the lack of surface active sites, and the defect-riched nature of BP. Herein, we report that BP nanosheets decorated with in situ grown Pt (BP NSs/Pt) could act as a highly efficient catalyst for photocatalytic H2 evolution in an Erythrosin B (ErB)-sensitized system under visible light irradiation (>= 450 nm) in the presence of triethanolamine (TEOA) as sacrificial electron donor. It is found that BP NSs can provide large surface area for the confined growth of Pt nanoparticles with a high dispersion and a reduced size but also stabilize the loaded Pt nanoparticles by covalent bonds at the BP NSs/Pt interfaces. Moreover, BP NSs offer a fast electron transfer pathway to facilitate the photocatalytic HER over in situ grown Pt catalyst. As a result, BP NSs/Pt catalyst exhibits similar to 6 times higher H-2 evolution activity than free Pt nanoparticles and an apparent quantum yield (AQY) of 0.57% at 500 nm irradiation in Er-BTEOA system. This work indicates the potential of BP NSs as an effective 2D matrix to construct numerous high performance photocatalysts and photocatalytic systems. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.