Efficient photocatalytic degradation of imidacloprid by sulfur vacancy-modified MOF808-EDTA/S-Zn3In2S6 Z-scheme heterojunction: Synergistic effects of EDTA-mediated morphological control and interfacial In–O bond

The excessive use of imidacloprid (IMD) poses a severe threat to human health and ecological stability. This study uniformly anchors MOF808 to the edges of Zn 3 In 2 S 6 nanosheets with sulfur vacancies by introducing EDTA ligands onto MOF808, successfully constructing a MOF808-EDTA/S-Zn 3 In 2 S 6 (MEZ) Z-scheme heterojunction for the efficient degradation of IMD. The presence of sulfur vacancies and interfacial In-O bonds in MEZ facilitates the enrichment of electrons on the S-Zn 3 In 2 S 6 side, thereby enhancing its ability to adsorb and activate oxygen and endowing MEZ with excellent photocatalytic activity. The optimized MEZ achieves a degradation rate of 98.4 % for IMD, with rate constants 5.0 and 76 times higher than those of S-Zn 3 In 2 S 6 and MOF808, respectively. After five photocatalytic cycles, MEZ still retains over 90 % photocatalytic activity, demonstrating the excellent stability of the surface catalyst, which can be successfully applied to the degradation of IMD in actual water. Singlet oxygen, superoxide radicals, and hydroxyl radicals preferentially attack the C7, C9, and N14 sites of IMD, leading to hydroxylation, denitration, ring-opening reactions, and dealkylation. These reactions decompose IMD into smaller products and significantly reduce IMD’s environmental risks. This study proposes an effective strategy to regulate the distribution of metal–organic frameworks on semiconductor surfaces and offers new insights for rationally developing Z-scheme photocatalysts to remove emerging pollutants in environmental remediation.