An Efficient ZnIn2S4@CuInS2 Core–Shell p–n Heterojunction to Boost Visible-Light Photocatalytic Hydrogen Evolution

The efficient separation of photoexcited electrons and holes is crucial for improving the activity of photocatalytic hydrogen evolution. Herein, an efficient core–shell p–n heterojunction of ZnIn 2 S 4 @CuInS 2 microflowers has been devised and fabricated by two-step hydrothermal method. The results revealed that the marigold-like microspheres of ZnIn 2 S 4 @CuInS 2 heterojunction consisted of thin nanosheets, matched well in the lattice, and had a large interface contact area, which boosted charge separation and transfer for solar hydrogen production. Moreover, the intimate interfacial contact between n-type ZnIn 2 S 4 and p-type CuInS 2 resulted in the formation of unique p–n heterojunction, which further promoted charge separation due to the built-in electric field. As a consequence, the ZnIn 2 S 4 @CuInS 2 photocatalyst with 5 atom % CuInS 2 showed the highest production of H 2 evolution (about 1168 μmol·g –1 ) among all prepared photocatalysts, which was nearly 4-fold the amount of the hydrogen production for the pristine ZnIn 2 S 4 . Therefore, the core–shell p–n heterojunction is an efficient structure design for the utilization of solar energy to obtain clean energy.