Molecular Engineering of Porous Organic Frameworks for Tailored Photocatalytic Activity in Environmentally Relevant Processes

Ensuring a reliable supply of clean water is an increasingly urgent global priority due to the rising occurrence of pollutants such as microplastics, recalcitrant organic molecules, and toxic metal ions. To address these challenges, advanced treatment technologies capable of selectively degrading or transforming persistent contaminants are needed. Among the emerging strategies, light‑driven catalytic processes are attracting significant attention for their potential to harness renewable energy to eliminate complex pollutants. Porous organic materials, ranging from crystalline Covalent Organic Frameworks (COFs) to amorphous architectures such as Covalent Triazine Frameworks (CTFs), Conjugated Microporous Polymers (CMPs), and Porous Aromatic Frameworks (PAFs), offer exceptional tunability and have recently shown promise as efficient heterogeneous photocatalysts.

To deepen the understanding of these systems, we have synthesized and investigated several families of CMPs, CTFs, and PAFs with systematically varied chemical structures. Despite sharing similar morphological and photophysical features, these materials exhibit strikingly different behaviors in photocatalytic tests relevant to water purification, including the oxidative degradation of organic pollutants and the reduction of Cr(VI) species. Our combined experimental and computational analyses reveal that small variations in connectivity, electronic distribution, and molecular design govern key charge‑transfer and light‑absorption processes.

Overall, our results show that targeted structural modifications, such as nitrogen incorporation, strategic substitution with electron‑donating or electron‑withdrawing groups, and the introduction of functional fragments with specific affinity for selected pollutants, allow precise tuning of the photocatalytic response. These insights highlight the potential of porous organic networks as highly adaptable platforms for a variety of photocatalytic water‑treatment applications.