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 Eu3+ doped CdSe quantum dots with hydrophilic alloy shell CdS/CdZnS/ZnS and anchored it on flower-like ZnIn2S4 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 ZnIn2S4. Furthermore, the creation of S-scheme heterojunction improves the disadvantages of ZnIn2S4 in visible light absorption and accelerates charge separation markedly. This work provides a distinctive perspective on the photocatalysts of photocatalytic hydrogen evolution. [Display omitted] •Cd(Eu)Se/CdS/CdZnS/ZnS core/shell QDs were fabricated to reduce defects.•Cd(Eu)Se/CdS/CdZnS/ZnS were changed to water solubility by ligand exchange.•Flower-like ZnIn2S4 and Cd(Eu)Se/CdS/CdZnS/ZnS formed S-scheme heterojunction.•The H2 evolution rate reached 3888.79 μmol‧g−1‧h−1, 6 times higher than ZnIn2S4.