Fabrication of CdS/Pt/MIL-125 with Effective Spatial Separation for Improved Visible-Light Catalytic H₂ Evolution Using γ‑Ray Irradiation

Hydrogen is a very promising green energy alternative to fossil fuel owing to both environmental friendliness and high-energy nature; however, improving the hydrogen production efficiency of photocatalysts under visible light has remained a challenge. Herein, CdS/Pt/MIL-125 nanocomposite has been fabricated using γ-ray irradiation, where Pt and CdS nanoparticles with clean surfaces are well dispersed inside and on the surface of MIL-125, respectively, which greatly promotes effective space separation of photogenerated carriers and thus improves the visible-light catalytic activity. The hydrogen generation rate of CdS/Pt/MIL-125 nanocomposite is found up to 6783.5 μmol/(g·h) under visible-light illumination, which is 7.3 times that of CdS/MIL-125 without Pt as electron trap reservoirs and 4.4 times that of Pt/CdS/MIL-125 without effective spatial separation between CdS and Pt. The reason is attributed to the synergy of ternary CdS/Pt/MIL-125 with a unique ordered mesoporous structure that may widen the absorption range of the light, improve the efficiency of light harvesting, facilitate mass transfer, prevent the aggregation of CdS and Pt nanoparticles, suppress the electron–hole (e–h) pair recombination, and provide more active sites. Moreover, the loading amount of Pt or CdS nanoparticles also affects the activity of CdS/Pt/MIL-125 nanocomposite for visible-light catalytic H₂ evolution. In view of the extensive use of γ-ray irradiation in industry, this research presents a rational route to the fabrication of novel hybrid photocatalysts for improved visible-light catalytic hydrogen evolution.