Morphological Engineering of Zn(II)-Tripyridine Supramolecular Catalysts for CO ₂ Photoconversion to CO

In this study, we designed and synthesized a novel organic ligand (<b>L3Tpy</b>) using lysine as a bridging unit and terpyridine as the core coordinating group. A <b>Zn-L3Tpy</b> coordination polymer gel (CPG) was subsequently prepared via a facile one-step ultrasonic treatment of a precursor solution containing <b>L3Tpy</b> and ZnCl₂ in <i>N</i>,<i>N</i>-dimethylformamide (DMF). Comprehensive characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) revealed that the gel possesses a short-range ordered lamellar stacking structure. Photocatalytic CO₂ reduction experiments demonstrated that the <b>Zn-L3Tpy CPG</b> achieved a CO production rate of 24 μmol g^-1 h^-1, representing a 2-fold enhancement over its nongelated <b>Zn-L3Tpy</b>. Photoelectrochemical analysis further indicated that the short-range ordered lamellar structure facilitated efficient charge mobility, thereby significantly improving the CO₂ reduction performance. This work presents a viable structural optimization strategy to enhance the photocatalytic efficiency of metal-organic complexes for sustainable CO₂ conversion.