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

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. What is interesting is that during the reduction process by γ-ray irradiation, MOFs are partially or completely hydrolyzed to TiO₂ nanosheets, forming the unique yolk-shell or hollow structure. The hydrogen production rate is 2983.5 μmol·g^-1·h^-1 for yolk-shell structures and 1934.2 μmol·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.