An in-situ growth approach to 2D MoS2-2D PbS heterojunction composites with improved photocatalytic activity

The advantage of 2D-2D heterojunction over 2D-0D and 2D-1D heterojunction is that it has larger interface area, which results in the shorter migration distance of photo-induced charge carriers, and can therefore separate the electron-hole pairs more effectively. In this work, to form 2D-2D heterojunction, PbS nanosheets were grown in situ on 2D MoS2 layers via. solvothermal process. The formation of 2D MoS2-2D PbS composites has been confirmed by XRD, Raman, TEM, and EDS analysis. The area of PbS nanosheets attached on MoS2 can be controlled by changing the concentration of PbS precursor in reaction solution. Compared with pristine MoS2, MoS2-PbS composites showed improved light absorption property and enhanced photocatalytic ability using methylene blue as the target of degradation. The optimized composite displayed a photocurrent 5 times higher than that of pristine MoS2.