Hua Sun

Tailoring polymeric carbon nitride (CN) to simultaneously broaden its light absorption range and improve charge carrier mobility remains a key challenge for photocatalytic H ₂ O ₂ production. The molecular junction strategy has been proven to be an effective approach to address the aforementioned challenges. In this work, we developed a molecular junction through controlled thermal ring‐opening isomerization of benzoguanamine, thereby creating a well‐defined C‐C‐bridged benzene‐heptazine molecular junction. Experimental and theoretical studies reveal that: (1) Benzene functionalization extends the π‐conjugation, enabling n→π* transitions for broad‐spectrum absorption; (2) The donor‐acceptor structure enhances self‐polarization effects, strengthening the built‐in electric field for efficient charge separation; (3) The unique molecular architecture overcomes traditional kinetic limitations, enabling a dual‐channel H ₂ O ₂ synthesis mechanism. The optimized catalyst achieves remarkable production rates of 5222 µmol∙g ^{− 1} ∙h ^{− 1} in isopropanol/water and 1587 µmol∙g ⁻¹ ∙h ⁻¹ in pure water, representing 13.1‐fold and 32.4‐fold improvements over pristine CN, respectively. This work advances molecular‐scale design of photocatalysts and offers new strategies for artificial photosynthesis.

This work demonstrates that oligoethylene glycol side-chain length on F8BT directly governs exciton lifetime and dipole moment, thereby systematically tuning photocatalytic hydrogen evolution performance.