MIL-125(Ti)@ZIF-67-derived MIL-125(Ti)@TiO2 hollow nanodiscs decorated with Co3S4 for remarkable photocatalytic CO2 reduction

Fabricating photocatalysts with customizable structure and composition using different metal-organic framework (MOF) building blocks has intriguing implications in chemistry and material science, but it is challenging to do so. Here, a two-step synthetic strategy was designed to prepare MIL-125(Ti)@TiO2 hollow nanodiscs decorated with Co3S4 nanoparticles for CO2 photoreduction. The Co-based zeolite imidazolium ester backbone (ZIF-67) nanolayer was first loaded on the prepared MIL-125(Ti) nanodiscs to form core@shell MIL-125(Ti)@ZIF-67 nanodiscs. The following sulfidation process under solvothermal condition led to the production of MIL-125(Ti)@TiO2 hollow nanodiscs decorated with Co3S4 nanoparticles (MIL-125(Ti)@TiO2\Co3S4). This ternary hybrid catalyst with hollow nanodisc structure possessed a significantly enhanced charge separation efficiency and visible light absorption, along with offering a huge number of active sites. Considering the above advantages, the CO2 photoreduction activity of the optimized MIL-125(Ti)@TiO2\Co3S4 catalyst was significantly increased when compared to single-component catalysts (MIL-125(Ti), TiO2, and Co3S4) and binary hybrid catalysts (MIL-125(Ti)@TiO2 and TiO2\Co3S4) under simulated sunlight irradiation. CO is the main product with a productivity of 587.50 & mu;mol g(-1) h(-1), which is almost seven times higher than that of pure MIL-125(Ti). The potential photocatalytic mechanism of the hybrid photocatalyst has also been demonstrated. This study presents a simple and effective technique for fabricating MOF-based hybrid catalysts for photocatalytic applications.