Polymorphism in Covalent Organic Frameworks Regulates Excited Dynamics for H2O2 Photosynthesis Coupled With Biomass Valorization.
Polymorphism in covalent organic frameworks (COFs) offers a unique platform to decipher structure-property relationships, yet its impact on excited-state dynamics remains unexplored. Herein, we construct two chemically identical but topologically distinct 1D and 2D COF polymorphs to correlate framework architecture with photocatalytic performance. Impressively, in H2O2 photosynthesis coupled with furfuryl alcohol valorization, the 1D-TBPP-COF showed an exceptional H2O2 generation rate (18.75 mmol g-1 h-1) and selective oxidation of furfuryl alcohol to high-value 6-hydroxy-2H-pyran-3(6H)-one (PN) with PN formation rate of 28.14 mmol·g-1·h-1, substantially outperforming the 2D-TBPP-COF counterpart. Mechanistic investigations revealed that the intercalated dual-chain edges in 1D-TBPP-COF impose steric constraints on aromatic ring rotation, effectively suppressing vibrational relaxation losses and prolonging the charge-transfer state lifetime. In contrast, the conformationally flexible 2D-TBPP-COF permits greater rotational freedom, leading to non-radiative energy dissipation. This work establishes polymorphism engineering as a powerful strategy to manipulate excited-state dynamics in COFs for photocatalysis.