Fabrication for improved photocatalytic H₂ production using γ-ray irradiation: Yolk-shell and hollow structures derived from MIL-125

The yolk-shell MIL-125/TiO₂/ Pt/CdS and hollow TiO₂/Pt/CdS visible-light catalysts were successfully synthesized from MIL-125 by γ-ray irradiation. During the reduction process by γ-ray irradiation, metal organic frameworks are partially or completely hydrolyzed to TiO₂ nanosheets, forming the unique yolk-shell or hollow structure. The hydrogen production rate is 2.9835 mmol·g⁻¹·h⁻¹ for yolk-shell structures and 1.9342 mmol·g⁻¹·h⁻¹ for hollow structures under visible-light illumination, which is 7.9 and 5.1 times higher than that of CdS, respectively. The excellent properties of these photocatalysts may be attributed to the effective absorption and utilization of the light, the porous yolk-shell or hollow structure derived from MIL-125 to facilitate mass transfer, and close contact among CdS nanoparticles, TiO₂ nanosheets and Pt nanoparticles to improve the separation of electron-hole pairs. This research can provide a simple and new method for the construction of high efficiency photocatalysts derived from MOFs using the γ-ray irradiation.