Construction of a Donor−Acceptor Zinc-Based Organic Framework Incorporating a Benzothiadiazole Photosensitizer for Efficient Photocatalytic Dye Degradation

Abstract

Photocatalytic degradation has emerged as a sustainable and efficient alternative for mineralizing organic contaminants, owing to its utilization of abundant energy sources and environmental compatibility. To achieve efficient mineralization of organic pollutants in aqueous environments, a photosensitive zinc-based metal−organic framework (MOF), denoted as ZnL1, was synthesized. This framework incorporates mixed ligands with staggered energy levels, coordinated through zinc ions to function as complementary electron donors and acceptors. This design facilitates efficient photoinduced electron transfer (PET), significantly enhancing photocatalytic performance. ZnL1 achieves a degradation efficiency exceeding 99% for three common aromatic dyes, including rhodamine B, methyl orange, and congo red. Density functional theory (DFT) calculations indicate that the superior activity for ZnL1 originates from a PET process between the electron-donating ligand 2,5-dichloroterephthalic acid (H2DCA) and the electron-accepting ligand 4,7-di(pyridin-4-yl)benzothiadiazole (PBT), which generates •O2− radicals required for the degradation of dye. This study presents a viable strategy for the development of high-performance heterogeneous MOF photocatalysts for organic contaminant remediation.