Spatially Separated Redox Centers in One-Dimensional Sp²-Carbon Covalent Organic Frameworks Enable Synergistic...

The simultaneous recovery of precious metal and pollutant degradation is often hindered by competing redox processes. Herein, we address this condition by designing a one-dimensional covalent organic framework (COF), olefin-linked iridium COF (Ole Ir-COF²⁺), featuring a donor-acceptor-acceptor cascade. Ir complexes and pyrene units form a dual photosensitizing system enabling broad-spectrum absorption, while quaternized bipyridine groups precisely modify the framework edges to create a cationic interface that selectively anchors PdCl₄ ^2-. The fully conjugated backbone establishes spatially separated oxidation (Ir/pyrene) and reduction (bipyridinium) centers, synergistically promoting efficient mass transfer and directional charge transport. Ole Ir-COF²⁺ exhibits a carrier lifetime of 5.06 ns (threefold longer than Ole COF⁴⁺) and an ultralow exciton binding energy of 25.3 meV (half that of Ole COF⁴⁺). Without sacrificial agents, it achieves a palladium [Pd(II)] extraction capacity of 1749 mg g^-1 (twofold higher than that of Ole COF⁴⁺) and a bisphenol A (BPA) degradation rate constant of 0.1710 min^-1.