Morphological Engineering of Zn(II)-Tripyridine Supramolecular Catalysts for CO2 Photoconversion to CO

Abstract

In this study, we designed and synthesized a novel organic ligand (L3Tpy) using lysine as a bridging unit and terpyridine as the core coordinating group. A Zn-L3Tpy coordination polymer gel (CPG) was subsequently prepared via a facile one-step ultrasonic treatment of a precursor solution containing L3Tpy and ZnCl₂ in N,N-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 Zn-L3Tpy CPG achieved a CO production rate of 24 μmol g^-1 h^-1, representing a 2-fold enhancement over its nongelated Zn-L3Tpy. 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.