Unveiling the dual charge modulation of built-in electric field in metal-free photocatalysts for efficient photo-Fenton-like reaction

Herein, we delved into the dual charge modulation of built-in electric field (BIEF) within photocatalysts on degradation of bisphenol A (BPA) via a photocatalysis coupling peroxymonosulfate activation (PC-PMS) system. Thiophene rings were incorporated into the carbon nitride conjugated structure (CN-TDC-X) to tailor the BIEF for enhanced PC-PMS mediated wastewater purification. Advanced characterizations and theoretical calculations confirmed that CN units of the planar heterojunction acted as electron donors in the dark, activating PMS to generate reactive oxygen species of SO4•− and •OH, and facilitating electron transfer process (ETP) via non-radical pathways. While the motifs containing thiophene rings served as electron donors under light irradiation, initiating the production of h+, O2•−, 1O2, and activating the ETP pathway. The dual sites modulation by BIEF contributed to the efficient degradation of BPA in PC-PMS system. The work provides valuable insights into the manipulator in photo-Fenton-like process for sustainable and environmentally-friendly water purification.