Advancing the integration of covalent-organic-framework with organic, inorganic, and polymeric materials for light-assisted green H₂ generation: A review of emerging trends

The growing demand for sustainable energy has driven significant advancements in covalent organic frameworks (COFs) for photocatalytic H₂ production. In this context, this review comprehensively examines the integration of COFs with various organic, inorganic, and polymeric materials to enhance light-assisted H₂ generation. We explore key synthesis approaches, including solvothermal, mechanochemical, sonochemical, interfacial, and post-synthetic modifications. Additionally, innovative methods such as photochemical synthesis, microwave-assisted solvothermal techniques, plasma-induced synthesis, and electron-beam-induced synthesis are discussed, highlighting their potential to optimize the structural and photocatalytic properties of COF-based heterojunction systems. Furthermore, extensive research has been conducted on the development of various composite materials, such as MOF-COF, metal oxide-COF, metal sulfide-COF, MXene-COF, g-C₃N₄-COF, and graphitic oxide-COF composites, to investigate their combined effects in improving photocatalytic efficiency. Particular attention is given to heterojunction systems and their structural features, which are critical for enhancing the photophysical and chemical properties required for efficient H₂ generation. Lastly, our findings reveal that the highest photocatalytic H₂ generation rate reported to date has been achieved using specific heterojunction systems. Successively, by synthesizing recent advancements and emerging trends, this review underscores the potential of COF-based composites to revolutionize sustainable energy solutions and provides valuable insights into future research directions aimed at significantly enhancing H₂ production efficiency under light irradiation.