Heteropore Conjugated Organic Reticular Subnano‐Crystal for Photocatalytic Water Splitting

ABSTRACT 2D COF‐based photocatalysts exist as insoluble and difficult‐to‐process blocks, the layered stacking buries active sites, hindering water molecule access, while crystal defects restrict charge carrier migration/penetration. The well‐defined sub‐nanostructures with distinct configurations ( C 2 , C 3 ) can construct multiple pathways and intramolecular electric fields, which promote electron separation and transfer. Hence, we develop a kind of heteropore‐conjugated reticular oligomers (CROs) subnano‐crystals with well‐defined structures, which can be regarded as a defect‐free COFs segment. These sub‐nanometer dots ensure sufficient exposure of active sites, enhance processability, form a “homogeneous catalyst” and consequently increase the accessibility of water molecules. Accordingly, the photocatalytic performance of series CROs is up to 129.33 μmol h –1 , improving 3–5 times over bulk COFs. Theoretical calculation shows that: Electron transfer number (ET) increased from 0.43 to 0.99 e, charge transfer distance ( D ) increases from 2.467 to 10.319 Å, while electron–hole overlap integral ( S r ) decreases from 0.495 to 0.023, and exciton binding energy ( E b ) decreases from 6.28 to 4.28 eV. The statistical product and service solutions (SPSS) method indicates that extending electron–hole separation distances and reducing exciton binding energy play a pivotal role in achieving effective electron delocalization and efficient charge transfer, thus significantly promoting the photocatalytic process.