Cd(Eu)Se/CdS/CdZnS/ZnS quantum dots with hydrophilic alloy shell supported by flower-like ZnIn2S4: A S-scheme for efficient photocatalytic H2 evolution

Photocatalytic hydrogen evolution via water splitting based on semiconductor technologies is a vital way to tackle environmental problems and the energy crisis in a sustainable manner. Carrier separation efficiency, light absorption capacity and microstructure of photocatalysts are key factors affecting the efficiency of photocatalytic hydrogen evolution. However, there exist problems like low separation of photogenerated electrons and holes and limited light absorption for traditional semiconductors. Here we prepared Eu ³⁺ doped CdSe quantum dots with hydrophilic alloy shell CdS/CdZnS/ZnS and anchored it on flower-like ZnIn ₂S ₄ to construct S-scheme heterojunction. Characterizations of photocatalytic performance indicate that the hydrogen production performance is improved. What can be found is that the optimized composite photocatalyst has photocatalytic hydrogen evolution efficiency of 3888.79 μmol‧g ⁻¹‧h ⁻¹ and it is 6 times higher than unmodified ZnIn ₂S ₄. Furthermore, the creation of S-scheme heterojunction improves the disadvantages of ZnIn ₂S ₄ in visible light absorption and accelerates charge separation markedly. This work provides a distinctive perspective on the photocatalysts of photocatalytic hydrogen evolution.