Multiple Heteroatom‐Hydrogen Bonds Bridging Electron Transport in Covalent Organic Framework‐Based Supramolecular System for Photoreduction of CO2

Abstract Supramolecular systems consisting of covalent organic frameworks (COFs) and Ni complex are designed for robust photocatalytic reduction of CO 2 . Multiple heteroatom‐hydrogen bonding between the COF and Ni complex is identified to play a decisive role in the photoexcited electron transfer across the liquid‐solid interface. The diminution of steric groups on COF or metal complex can optimize catalytic performance, which is more attributable to the enhanced hydrogen‐bond interaction rather than their intrinsic activity. The photosystem with relatively strong strength of hydrogen bonds exhibits remarkable photocatalytic CO 2 ‐to‐CO conversion, far superior to photosystems with supported atomic Ni or metal complex alone in the absence of hydrogen‐bond effect. Such heteroatom‐hydrogen bonds bridging electron transport pathway confers supramolecular system with high photocatalytic performance, providing an avenue to rationally design efficient and steadily available photosystems.