A novel 2D/2D MoSe2/SnSe heterojunction photocatalyst with large carrier transmission channel shows excellent photoelectrochemical performance

Highlights: • 2D/2D face-to-face MoSe₂/SnSe heterojunction photocatalysts were prepared. • The photoelectrochemistry activity of the MoSe₂/SnSe heterojunction photocatalysts is largely enhanced. • The photocurrent of the MoSe₂/SnSe heterojunction photocatalyst can reach 26.2 μA/cm². • The EIS results confirm the internal resistance of MoSe₂/SnSe heterojunction photocatalyst is much low. A novel 2D/2D face-to-face MoSe₂/SnSe heterojunction photocatalysts have been successfully obtained from SnSe nanosheets and MoSe₂ nanoplates. These MoSe₂/SnSe heterojunction photocatalysts show well full spectrum absorption. The XPS results demonstrate obvious peaks shift of Sn 3d and Se 3d which reveals a binding was formed between SnSe and MoSe₂ and MoSe₂/SnSe heterojunction can be also confirmed by the TEM images. Pristine SnSe has a high photocurrent of 8.6 μA/cm² which is much higher than many other metal sulfides and selenides such as SnS₂ (1.5 μA/cm²), In₂S₃ (1.0 μA/cm²), MnS (1.6 μA/cm²), MoS₂ (0.73 μA/cm²), MoSe₂ (0.58 μA/cm²), ZnSe (0.94 μA/cm²) and FeSe₂ (0.49 μA/cm²) in our previous work. This MoSe₂/SnSe heterojunction photocatalyst shows excellent photoelectrochemical performance improvement by 3 times than pristine SnSe under a compositing ratio of 5.0% MoSe₂. The photocurrent of the heterojunction photocatalyst can reach 26.2 μA/cm². The large improvement of photoelectrochemical performance can be ascribed to the 2D/2D face-to-face contact between SnSe nanosheets and MoSe₂ nanoplates. There is carriers' transmission channel between the heterojunction which can improve the separation efficiency. The work develops a potential new energy material.