Bandgap engineered phenanthrenequinone-based donor–acceptor conjugated microporous polymers for ultrafast photocatalytic removal of tetracycline

Abstract

The widespread presence of antibiotics such as tetracycline (TC) in the environment has become a serious concern due to their role in promoting antibiotic resistance, disrupting microbial ecosystems, and bioaccumulation, thereby posing public health risks through food chain exposure and potential allergic reactions. There is an urgent need for ultrafast removal technologies that overcome challenges such as incomplete degradation, the formation of toxic intermediates, interference from coexisting species, and limited catalyst stability, which hinder practical applications. In this study, we develop two phenanthrenequinone-based conjugated microporous polymers (CMPs), TRZ–PHQ and TPA–PHQ, by strategically tuning the electron-donating moieties to optimize their photophysical and photoelectrochemical properties for efficient TC degradation. Among them, the triazine-based CMP, TRZ–PHQ, demonstrated outstanding photocatalytic performance, achieving a record-breaking 99% degradation of tetracycline within just 15 minutes under visible-light irradiation, which represents the fastest degradation time reported to date. The superior activity of TRZ–PHQ is attributed to the synergistic effects of its unique triazine-based structure, an optimal energy bandgap of 2.06 eV, favorable alignment of conduction and valence bands, and low charge-transfer resistance, all of which enable efficient generation and transfer of photo-induced electron–hole pairs. These findings position TRZ–PHQ as a highly promising photocatalyst for the remediation of antibiotic-contaminated water, offering new opportunities for next-generation environmental purification technologies.