Enhanced CO 2 Photoconversion Efficiency in Atomic Co Immobilized Covalent Organic Frameworks Heterostructure via Boosting Charge Dynamics and Active Site Accessibility

Abstract Photocatalytic conversion of CO 2 into fuels and chemicals is of great significance for advancing sustainable development, yet its conversion efficiency remains constrained by inefficient charge separation and poor catalytic activity. Herein, a hybrid heterostructure is fabricated by in situ growth of bipyridine and triazine containing covalent organic frameworks (COFs) on SnS 2 nanosheets. Based on this heterostructure, a molecular engineering strategy is subsequently employed to design highly active single Co sites coordinated by bipyridine‐N motifs featuring distinctive electronic moieties. As a result, the optimized photocatalyst (SnS 2 /Co‐TAPT‐Bpy) enables an exceptional photocatalytic performance toward CO production under visible light irradiation with tunable CO/H 2 ration via changing the components of the heterojunctions. Experimental and theoretical investigations confirm that the photogenerated electrons can efficiently transfer from the SnS 2 component to the Co‐TAPT‐Bpy component through the interfacial electron field. More impressively, the electron‐deficient triazine motifs in Co‐TAPT‐BPy direct these photogenerated electrons toward the Co (II) active sites for CO 2 reduction. These atomically dispersed N‐Co‐N sites enhance CO 2 activation and protonation through d‐π orbital interactions, and suppress the competing H 2 evolution reaction, thus facilitating CO 2 conversion. This work highlights the potential of molecular regulation within heterojunctions to boost photocatalytic CO 2 conversion efficiency by optimizing charge dynamics and reaction site accessibility.