Cu-based MOFs/TiO ₂ Chitosan Beads for Green Photocatalytic H ₂ Generation

Designing supported photocatalysts for photocatalytic hydrogen production is essential to overcome the time-consuming or expensive photocatalyst post-collection additional step. Herein, a copper-based Metal–Organic Framework (MOF)/TiO2 (HKUST-1/TiO2) composite photocatalyst, very promising for hydrogen generation, was encapsulated in chitosan (CS) spherical beads. These millimeter-sized photocatalytic beads were synthesized via a three-step method, and diffuse reflectance as well as Fourier-transform infrared spectroscopies assert that HKUST-1/TiO2 is not altered by the synthesis process. Moreover, time-resolved microwave conductivity (TRMC) characterization proves that the charge carriers’ dynamics is not altered by the encapsulation of HKUST-1/TiO2. The beads possess a good photocatalytic activity for hydrogen generation under UV–visible light. The number of beads and their stability with cycling were also investigated. A significantly higher hydrogen generation with hydrated beads (459 μmol/g/h) was measured compared to the one with dried beads (45 μmol/g/h) according to better water and hydrogen diffusion in the hydrated beads. The highest production rate reaches 854 μmol/g/h with 4 HKUST-1/TiO2 CS beads loaded with 0.36 mg of photocatalyst per bead. Recyclability tests reveal good durability without a significant loss in efficiency.