Dual‐Functional Benzotrithiophene‐Based Covalent Organic Frameworks for Photocatalytic Detoxification of Mustard Gas Simulants and Antibacterial Defense

Abstract The persistent threats posed by toxic chemical warfare agents (CWAs) such as mustard gas (bis(2‐chloroethyl) sulfide, HD) and bacterial contaminants demand the development of innovative, sustainable mitigation strategies. Photocatalytic processes that generate reactive oxygen species (ROS) offer a promising dual‐functional approach for both chemical detoxification and antibacterial defense. In this study, two structurally analogous covalent organic frameworks (COFs), BPY‐COF and BD‐COF, are synthesized using benzotrithiophene as the donor unit paired with bipyridine and biphenyl, respectively. These COFs exhibit high crystallinity, broad‐spectrum light absorption, and efficient charge carrier transport, with BPY‐COF demonstrating superior performance due to the incorporation of heteroatoms. BPY‐COF achieved ultrafast detoxification of the mustard gas simulant 2‐chloroethyl ethyl sulfide (CEES) with a half‐life of 35 min and 100% selectivity for 2‐chloroethyl sulfoxide (CEESO) under white LED light, outperforming BD‐COF. Additionally, electrospun composite fibers containing 40 wt.% BPY‐COF maintained comparable CEES degradation rates and exhibited over 99% antibacterial efficiency against Escherichia coli and Bacillus subtilis within 60 min. These findings highlight the potential of BPY‐COF as a multifunctional photocatalyst for integrated applications in chemical detoxification and antibacterial defense, addressing critical challenges in public health and safety.