Chiralizing Covalent Organic Frameworks to Boost H 2 O 2 Photosynthesis

ABSTRACT Solar‐driven H 2 O 2 photosynthesis offers a sustainable route to on‐site oxidant production, yet the selective reduction of triplet O 2 to spin‐paired H 2 O 2 remains kinetically challenging. Covalent organic framework (COF) photocatalysts have largely focused on charge separation and active‐site reactivity, while overlooking the spin character of electrons transferred to O 2 . Here we discover that chiralization renders COFs significantly enhanced production of H 2 O 2 , and report a chiralization strategy for spin‐regulated H 2 O 2 photosynthesis in β‐ketoenamine‐linked COFs. The chiral frameworks enable spin‐selective electron transport, favor the O–O‐bond‐preserving reduction pathway and lower the apparent kinetic barrier for H 2 O 2 formation. Chiralization enhances H 2 O 2 production by 38.7%–252.1% relative to achiral counterparts. A bipyridine‐containing chiral COF reaches 22.8 mmol g −1 h −1 using solely water and oxygen, with an apparent quantum yield of 10.3% at 420 nm, placing it at the forefront of sacrificial‐agent‐free COF systems. Membrane‐integrated chiral COFs enable continuous‐flow H 2 O 2 production. These findings establish chirality as a design parameter coupling spin‐selective electron transport with O 2 reduction pathway control, opening new directions for COF photocatalysis.