Terbium-doped metal-organic frameworks: Dielectric and ferroelectric properties with enhanced electrochemical sensing for heavy metal ion detection

Abstract

Metal-Organic Frameworks (MOFs), specifically luminescent ferroelectric MOFs, have shown significant promise in applications like chemical sensing due to their unique structural and dielectric properties. This study focuses on the synthesis of Sr-BDC-based MOF (Strontium benzene dicarboxylate) doped with Tb (Terbium) metal using a hydrothermal method and their evaluation for electrochemical sensing of heavy metal ions, particularly zinc (Zn²⁺). The integration of Tb into the MOF structure enhances its electrochemical sensing capabilities by improving sensitivity and selectivity through the creation of specific binding sites and enhancing signal transduction mechanisms. The Tb-doped MOFs are synthesized under controlled hydrothermal conditions, allowing for precise incorporation of Tb ions into the MOF structure, which not only modifies the material's luminescent properties but also optimizes its ferroelectric behavior. Various characterization techniques confirm the successful doping and formation of a highly crystalline structure. X-ray diffraction (XRD) patterns reveal the distinct crystalline phases, while Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analyses provide insight into the morphology and elemental composition, respectively. Optical studies further affirm the luminescent properties of the Tb-doped MOFs, confirming their structural integrity and potential for sensing applications. Electrochemical investigations, including cyclic voltammetry (CV) and differential pulse voltammetry (DPV), highlight the superior performance of these Tb-doped MOFs in detecting Zn²⁺ ions. The material demonstrates high sensitivity, with a detection limit as low as 4 parts per million (ppm), making it highly effective for environmental monitoring and heavy metal detection. Additionally, the ferroelectric and dielectric properties of Tb-doped MOFs were explored, revealing enhanced polarization and dielectric response, making these materials promising for advanced technological applications in environmental monitoring and beyond. Overall, the integration of Tb into the MOF structure not only improves its luminescent and electrochemical properties but also makes it a versatile material with promising applications in environmental monitoring, chemical sensing, and potentially in next-generation electronic devices. The enhanced ferroelectric and dielectric properties open avenues for further exploration in multifunctional materials.