Black phosphorus: an efficient co-catalyst for charge separation and enhanced photocatalytic hydrogen evolution

Black phosphorus (BP), a phosphorus analog of graphene, is a two-dimensional material with the thickness-dependent bandgap and a high carrier mobility, which emerges as a promising material in nanoelectronics and optoelectronics. In this study, BP loaded with surface hydroxyl has been prepared by liquid ultrasonic exfoliation and used as the co-catalyst, which results in 341% photocatalytic hydrogen evolution enhancement to the anatase TiO2 under the simulated sunlight irradiation and a quantum efficiency as high as 18.23% at 365 nm. The improved photocatalytic activity has been ascribed to the Z-scheme mechanism. These results indicate that 2D surface hydroxyl-loaded BP can be used as a broadband photocatalyst by forming type II heterostructures with other wide-bandgap semiconductors.