Construction of Broad-Spectrum-Responsive D–A Type COF Photocatalysts with Mechanistic Insights into Visible-Light-Driven Tetracycline Degradation

A donor–acceptor (D–A) covalent organic framework (CoPcPA-COF) was constructed from a metal phthalocyanine donor and a polycarboxylic acid acceptor unit. Molecular structure modulation endowed the material with exceptional visible-light absorption (bandgap: 1.34 eV) and a strong photoelectronic response. In photocatalytic tetracycline degradation, CoPcPA-COF achieved 91.1% removal within 60 min and maintained stable performance in various real water matrices, demonstrating excellent environmental adaptability. Density functional theory (DFT) analysis revealed pronounced spatial charge separation (CT ratio: 88.97%), a high exciton binding energy (4.314 eV), and a ligand-to-metal charge transfer tendency. Density of states (DOS) calculations indicated a theoretical bandgap of 0.5 eV, corroborating its broad-spectrum light response and favorable electronic structure. This work provides a theoretical foundation for the development of visible-light-driven COF photocatalysts and offers a promising strategy for efficient remediation of antibiotic contamination in water.