SiO2@TiO2 Core@Shell Nanoparticles Deposited on 2D-Layered ZnIn2S4 to Form a Ternary Heterostructure for Simultaneous Photocatalytic Hydrogen Production and Organic Pollutant Degradation

It is challenging to design and prepare difunctional photocatalysts for simultaneous photocatalytic wastewater purification and hydrogen (H2) energy production. In this study, a novel ternary heterostructure pholocatalyst, ZnIn2S4@SiO2@TiO2 (ZIS@SiO2@TiO2) was successfully prepared by simple sol-gel and solvothermal methods. The SiO2 nanospheres were used as a support to prevent the aggregation of TiO2 nanoparticles efficiently. The SiO2@TiO2 nanoparticles were uniformly inserted into the 2D-layered flowerlike ZnIn2S4 to form a ternary heterostructure that can efficiently improve the separation and transportation of photoinduced electron-hole pairs. As expected, the 150%-ZIS@SiO2@TiO2 nanocomposite exhibited an excellent rate of H2 production under simulated sunlight (618.3 μmol g-1 h-1), which was 229 and 3.3 times higher than the binary SiO2@TiO2 nanoparticles and pure ZnIn2S4. Furthermore, the degradation efficiency of methylene blue reached 99.7% during the H2 production process. These findings provided possibilities to couple energy conversion with environmental restoration.