Novel 3D/2D heterojunction photocatalysts constructed by three-dimensional In2S3 dandelions and ultrathin hexagonal SnS2 nanosheets with excellent photocatalytic and photoelectrochemical activities

In this work, three-dimensional In2S3 dandelions were coupled with embedded two-dimensional ultrathin hexagonal SnS2 nanosheets as 3D/2D heterojunction photocatalysts and related photocatalytic and photoelectrochemical activities were studied. Compared with pristine In2S3, this 3D/2D In2S3/SnS2 heterojunction exhibited excellent enhancement in photocatalytic and photoelectrochemical performance. The 3D/2D In2S3/SnS2 heterojunction composite with the highest activity displayed nearly 5 times enhancement in photocatalytic performance and 7 times increase in photoelectrochemical property. The excellent performance can be ascribed to the 3D/2D heterojunction structure and appropriate energy band structure between In2S3 and SnS2. As the conduction band and valence band of In2S3 are both higher than those of SnS2, the photo-induced electrons at the conduction band of In2S3 will flow into the conduction band of SnS2 while the photo-induced holes at the valence band of SnS2 will flow into the valence band of In2S3. In this way, the photo-induced carriers will separate into different semiconductors. In the 3D/2D heterojunction structure, the three-dimensional In2S3 offers a network structure to load SnS2 nanosheets, and this network structure can collect and transfer photo-induced carriers very well which leaded to a high carriers' separation efficiency. The work develops a new strategy to improve the heterojunction property for photocatalytic and photoelectrochemical application.