π–π Stacking Enhanced Generation of Reactive Species in Donor–Acceptor Heterojunctions for High-Efficiency Photocatalytic Degradation of Endocrine-Disrupting Compounds under Solar Light

The development of high-efficiency metal-free photocatalysts for eliminating endocrine-disrupting compounds continues to pose a considerable challenge. Herein, we report the rational design and fabrication of a green and efficient donor–acceptor heterojunction photocatalyst, PTQ10:Y6@CSC, via a robust π–π stacking strategy. Relative to the PTQ10:IEICO-4F system with weak π–π interactions, the PTQ10:Y6 heterojunction exhibits a significantly enhanced internal electric field, with an intensity 2.05 times greater. This reinforced internal electric field effectively promotes the dissociation of photogenerated excitons and extends the charge carrier lifetime to 1.473 ns (compared to 1.267 ns for PTQ10:IEICO-4F). As a result, the production efficiency of key reactive species (•O2– and h+) is substantially elevated, enabling the complete degradation of 20 ppm methyltestosterone within 40 min under simulated solar irradiation. The PTQ10:Y6@CSC composite also demonstrates remarkable cycling stability, retaining 97.89% of its initial activity after 16 consecutive runs. Moreover, combining density functional theory simulations with experimental analyses, this study elucidates the underlying photodegradation pathways and reaction mechanisms by identifying the vulnerable attack sites on the methyltestosterone molecule. These findings provide not only a high-performance photocatalytic system for endocrine-disrupting compounds remediation but also fundamental insights into the structure–property relationships governing π–π stacked heterojunctions.