Rational design of a novel p-n heterojunction based on 3D layered nanoflower MoS supported CoWO nanoparticles for superior photocatalytic hydrogen generation.

Enriching the active sites of catalysts and artificially regulating the directional migration of photogenerated carriers are effective means to improve the catalytic activity of photocatalysts. In this work, polyvinylpyrrolidone (PVP) is used as the morphological modifier to prepare MoS with three-dimensional (3D) nanoflower structure. Compared with two-dimensional (2D) MoS nanosheets, three-dimensional nanoflower structure weakens the van der Waals force between nanosheets and inhibits the stacking between layers, thus exposing the high-density active sites of MoS nanoflower. The CoWO nanoparticles are successfully anchored to MoS by in-situ growth, forming the MoS/CoWO p-n heterojunction photocatalyst. The high photosensitivity of MoS increases the utilization of MoS/CoWO p-n heterojunction to visible light. The unique 3D nanoflower structure of MoS results in that CoWO nanoparticles are dispersed well on the surface of MoS, which prevents CoWO agglomeration. Based on the high efficiency of charge separation, abundant active sites and excellent property of visible light response, the hydrogen evolution rate of MoS/CoWO-40 reached 9414.4 μmol g h.