The role of bandgap and interface in enhancing photocatalytic H2 generation activity of 2D-2D black phosphorus/MoS2 photocatalyst

Abstract

Black phosphorus (BP) has recently emerged as a promising photocatalyst for solar H2 generation, whereas its bulk crystal with a bandgap of 0.3 eV restricts the driving force for achieving efficient photocatalytic activity. Here, various-sized BP samples were prepared to investigate the role of bandgap in their photocatalytic activities. The results show that the photocatalytic performance of BP samples increases with the decreased layer numbers in the presence of MoS2 as a cocatalyst, which is related to the more sufficient driving force of fewer-layered BP nanosheets. Furthermore, large and intimate 2D nanojunctions formed in this smart 2D-2D BP/MoS2 can accelerate the photogenerated charge separation, resulting in the high photocatalytic H2 production activity. As expected, the 10% BP-10000 nanosheets/MoS2 photocatalyst exhibits the highest H2 evolution rate of 1286 μmol·h−1·g−1 under visible light irradiation (λ > 420 nm) with an apparent quantum yield of 1.2% at 420 nm, which is much higher than optimized Pt-loaded BP-10000 sample. Moreover, a considerable H2 generation rate of 341 μmol·h-1·g-1 is observed under irradiation of the 10% BP-10000 nanosheets/MoS2 photocatalyst with >550 nm light. It is further anticipated that this study could provide further insight into the design of efficient BP-based photocatalysts, thus offering extendable availability for the construction of noble-metal-free and visible/near-infrared responsive solar H2 generation system.