Well-organized migration of electrons for enhanced hydrogen evolution: Integration of 2D MoS 2 nanosheets with plasmonic photocatalyst by a facile ultrasonic chemical method.

The construction of a plasmonic photocatalyst is an efficient way to suppress detrimental electrons-holes recombination and extend the spectral range of light absorption in semiconductors. However, the facilitation effect in the aspect of electrons-holes separation is great limited as the lack of a driving force compelled the electrons or holes migration to surface catalytic sites makes them flow randomly in semiconductors. In this work, we confirm that the integration of MoS2 nanosheets formed two dimensional (2D) layered heterojunction with C3 N4 with Au-C3 N4 plasmonic photocatalyst can further enhance electrons-holes separation through the formation of Au-C3 N4 -MoS2 nanostructure by a facile ultrasonic chemical method. The integrated MoS2 nanosheets extract the electrons not only from C3 N4 due to a building up of 2D layered heterojunction but also from plasmonic Au via a "pipe" played by C3 N4 . The electrons "pump" role of the 2D MoS2 nanosheets makes electrons flow randomly turn into the well-organized migration direction, promoting the electrons-holes more efficient separation and lifetime prolongation. Meanwhile, MoS2 nanosheets also increase the light absorption of the photocatalyst owing to its inherent strength of the narrower band gap. Enabled by integration of 2D MoS2 nanosheets, the hydrogen production rate is 2.08 times higher than that of its counterpart Au-C3 N4. This work highlights a new window to employ 2D layered heterojunction for enhanced photocatalytic hydrogen evolution performance.