Cucurbit[8]uril as a Supermolecular Lock for Designing Dual-chain Conjugated Polymer for Enhanced H2O2 Production Photocatalyst.

Conjugated polymers (CPs) have garnered attention for their tailorable structure properties, particularly in the context of efficient photosynthetic hydrogen peroxide (H2O2) production. However, the challenge lies in the precise molecular engineering of CPs to facilitate differing reaction pathways, thereby enhancing H2O2 photogeneration efficiency. In this study, we developed dual-chain CPs (DC-CPs) with a distinctive architecture, employing the supramolecular host cucurbit[8]uril as a "molecular lock" to conjoin two polymer chains. The dual-chain configuration is designed to harbour a central reaction centre conducive to oxygen reduction, providing dual conduction pathways for reactant molecules. The existence of this central reaction center was confirmed through the in-situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy measurements and density functional theory (DFT) calculations. In addition, femtosecond transient absorption (fs-TAS), variable temperature fluorescence spectroscopy and time-resolved photoluminescence (TRPL) measurements reveal double-stranded structures favourable for carrier transport and reactive site activation between dual polymer chains. Ultimately, DC-CPs demonstrate up to a threefold increase in H₂O₂ production compared to their respective single-chain CPs (SC-CPs). This work adds significantly to the application of CPs for efficient H2O2 photogeneration through molecular engineering strategy.