Reinforced π-conjugated organosulfur PDI polymer boosting peroxymonosulfate activation for photocatalytic degradation of bisphenol A

The practical application of perylene diimide (PDI) supramolecules is significantly hampered by their structural instability, which manifests as dissociation under alkaline conditions and deterioration during cyclic reactions. A thiourea-functionalized perylene diimide polymer with a reinforced π-conjugated framework (T-PDI) was synthesized for visible-light-driven (Vis) peroxymonosulfate (PMS) activation. The enhanced π-conjugation, synergizing with sulfur doping, endowed T-PDI with superior visible-light absorption and charge separation efficiency compared to urea-functionalized PDI (U-PDI). Experimental and theoretical analyses revealed that the robust π-conjugated network facilitated strong π-π stacking and directed spatial separation of electron-hole pairs, effectively suppressing recombination. Consequently, the T-PDI/PMS/Vis system achieved complete degradation of bisphenol A within 17.5 min ( k  = 0.197 min −1 ), 1.5-times faster than the U-PDI/PMS/Vis system ( k  = 0.134 min −1 ). The system also demonstrated excellent stability over multiple cycles, broad pH adaptability, and strong resistance to common water matrix interferents. This work highlights the critical role of π-conjugation engineering in developing high-performance, metal-free polymer photocatalysts for advanced oxidation processes.