MnS coupled with ultrathin MoS2 nanolayers as heterojunction photocatalyst for high photocatalytic and photoelectrochemical activities

Nano-MnS were coupled with ultrathin two-dimensional MoS2 nanolayers as heterojunction photocatalysts. The well heterojunction contact can be confirmed by high resolution TEM images. The heterojunction composites display higher absorption intensity of visible light and the S XPS peaks show obvious shift. Compared with pristine MnS, this MnS/MoS2 heterojunction exhibited vast enhancement in photocatalytic and photoelectrochemical performance. The heterojunction composite with highest activity displayed 161% enhancement in photocatalytic activity, 2.6–11.5 times increase of photocurrent density. This vast improvement can be assigned to the energy band matching of MnS/MoS2 heterojunction. Both the conduction band and valence band of MnS are more negative than those of MoS2, the photo-induced electrons at the conduction band of MnS will transfer into the conduction band of MoS2 while the photo-induced holes at the valence band of MoS2 will transfer into the valence band of MnS. In this way, the photo-produced carriers will flow into different semiconductors and the carriers' separation efficiency is enhanced. The work develops a new approach to improve the heterojunction property for photocatalytic and photoelectrochemical application.