Modulating Micro‐Environments in Tri‐Motif Molecular Junction COF for to Boost Photocatalytic CO ₂ Reduction

Abstract Photocatalytic CO 2 reduction presents a promising strategy for advancing carbon neutrality. COFs serve as ideal photocatalytic platforms but face limitations from poor active site exposure and rapid charge recombination. Through a donor‐acceptor synergy strategy, the pre‐designed structural features of COFs enable atomic‐level micro‐environments engineering at catalytic sites, enhancing carrier dynamics. This work designed tri‐motif molecular junction‐type COFs by integrating triazine and vinyl‐benzene as catalytic centers and using functional regulation units to refine the micro‐environments for efficient HCOOH production. The incorporation of Br induced a structural transformation from the A‐D‐d‐D‐A fragments in COF to an A‐D‐A‐D‐A fragments, enhancing photogenerated electron separation and transfer. DFT calculations reveal that vinyltriazine functions as catalytic center, with alkenylbenzene and Schiff‐base moieties acting synergistically as the photosensitive units. Molecular junction reconstruction enhanced localized electron interactions at active sites, optimizing electron transfer efficiency in accordance, which matches the pre‐design. Notably, the preferential adsorption of H exhibit to modulates the micro‐environments around catalytic active sites, thereby enhancing the stability of CO 2 adsorption. This work elucidates the mechanism by localized electron density and charge separation affect photocatalysis through precise molecular‐level tuning of electron donor/acceptor strength, providing new insights for design tri‐motif molecular junctions COF catalysts.