Benzophenone-Based Polymers and Covalent Organic Framework for Photocatalytic Molecular Oxygen Activation

Photosensitization by photoactive materials requires well-designed molecular engineering to enable continuous photochemical processes. However, developing a heavy-atom-free (HAF) strategy to enhance the photoactivity of photosensitizers remains a significant challenge. In this study, we introduce a novel strategy to enhance photosensitization by incorporating benzophenone-rich components into 3D polymers ( BQP1 and BQP2 ) and the 2D covalent organic framework ( BQ-TMT COF ). This incorporation accelerates both charge carrier separation and intersystem crossing, thereby significantly improving photo-to-chemical energy conversion and electron transfer reactions. Notably, the crystalline BQ-TMT COF enables efficient photocatalytic molecular O 2 activation, producing both 1 O 2 and O 2 · – with high efficiency and recyclability. It demonstrates selective photocatalytic oxidation in 1 O 2 -mediated sulfide transformations. Moreover, the material performs well in O 2 · – -mediated oxidation, including the hydroxylation of boronic acids and oxidation of amines to imines. The BQ-TMT COF -based photoelectrode generates a photocurrent of approximately 20.7 μA·cm –2 at 0.4 V vs RHE and achieves a high photocatalytic hydrogen production rate. Our study demonstrates a HAF heterogeneous photosensitizer with efficient photoactive small molecule activation through molecular engineering.