Two-Dimensional–Layered Zn (II) Cyclophosphazene—Organic Framework for Effective Photocatalytic Removal of Organic Dyes

Abstract

A novel two-dimensional (2D) coordination polymer, formulated as {[Zn₂(trp)₂(L)]·DMF·3H₂O} (PCP-10), was synthesized via cyclophosphazene-based tetracarboxylate (H₄L) and N-donor terpyridine ligand (trp). The synthesis was achieved through solvothermal methods, and the structure underwent thorough characterization using techniques such as FT-IR, single crystal and powder XRD (SC and PXRD), thermal analysis, zeta potential, and UV-DRS. X-ray crystallographic analysis revealed that the cyclotriphosphazene ligand coordinated with Zn (II) ions, forming a 2D sheet-like structure. Remarkably, PCP-10 exhibited good efficacy in degrading various organic dyes such as MB, MO, and RhB under UVA light exposure, achieving degradation rates of up to 90%. High degradation performance of PCP-10 was attributed to the unique N-donor terpyridine ligand and its band gap properties. Additionally, the study elucidated the role of reactive oxygen species (ROS) in dye degradation, emphasizing the significance of superoxide radicals (O₂˙⁻). Scavenger experiments identified specific ROS involved in the degradation mechanism, aiding in customizing photocatalyst and scavenger systems. Furthermore, the durability of PCP-10 was assessed through repeated use testing, showcasing its high initial efficiency and minimal decline over five cycles, indicative of superior durability. In conclusion, this study underscores the potential of PCP-10 as an effective photocatalyst for environmental remediation, highlighting the importance of chemical composition and structural properties in optimizing photocatalytic performance. The solid-state photoluminescence properties of PCP-10 were also studied.