Construction of Hollow Co 3 O 4 @ZnIn 2 S 4 p-n Heterojunctions for Highly Efficient Photocatalytic Hydrogen Production.

Photocatalysts derived from semiconductor heterojunctions for water splitting have bright prospects in solar energy conversion. Here, a Co 3 O 4 @ZIS p-n heterojunction was successfully created by developing two-dimensional ZnIn 2 S 4 on ZIF-67-derived hollow Co 3 O 4 nanocages, realizing efficient spatial separation of the electron-hole pair. Moreover, the black hollow structure of Co 3 O 4 considerably increases the range of light absorption and the light utilization efficiency of the heterojunction avoids the agglomeration of ZnIn 2 S 4 nanosheets and further improves the hydrogen generation rate of the material. The obtained Co 3 O 4 (20) @ZIS showed excellent photocatalytic H 2 activity of 5.38 mmol g -1 ·h -1 under simulated solar light, which was seven times more than that of pure ZnIn 2 S 4 . Therefore, these kinds of constructions of hollow p-n heterojunctions have a positive prospect in solar energy conversion fields.