Rapid Synthesis of MIV-Based Multimetal–Organic Frameworks for Photopolymerization of Methyl Methacrylate under Visible Light

Metal-organic frameworks (MOFs) are porous materials that have attracted increasing interest for photocatalytic applications. Conventional solvothermal synthesis of photoactive MOFs typically requires high-pressure reactors and time-consuming preparative protocols. This study reports the preparation of Ti-, Zr-, and/or Hf-based MOFs using a hot injection approach. Among the prepared materials, NH₂-UiO-66 (Zr/Hf) exhibited high photocatalytic activity for the polymerization of methyl methacrylate under visible light irradiation and under monochromatic visible light at a wavelength of 430 nm (xenon lamp or light-emitting diode). The ability to produce these materials using simple, low-pressure equipment makes this method a promising route for process scale-up and cost reduction. The obtained MOFs demonstrated high photostability, maintaining nearly unchanged activity over three photocatalytic cycles and during long-term operation (44 h). Moreover, the polymer products were analyzed via size exclusion chromatography and complementary analytical techniques, thereby elucidating the photopolymerization process under different irradiation conditions and reaction times.