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 ZnIn2S4@CuInS2 microflowers has been devised and fabricated by two-step hydrothermal method. The results revealed that the marigold-like microspheres of ZnIn2S4@CuInS2 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 ZnIn2S4 and p-type CuInS2 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 ZnIn2S4@CuInS2 photocatalyst with 5 atom % CuInS2 showed the highest production of H2 evolution (about 1168 μmol·g–1) among all prepared photocatalysts, which was nearly 4-fold the amount of the hydrogen production for the pristine ZnIn2S4. Therefore, the core–shell p–n heterojunction is an efficient structure design for the utilization of solar energy to obtain clean energy.