Lanthanide f-orbitals in MOFs: Unlocking multifunctionality for corrosion protection, energy storage, and smart sensing

Abstract

The distinct electrical and magnetic characteristics of its lanthanide (Ln³⁺) ions have made lanthanide-based Metal-Organic Frameworks (Ln-MOFs) an important family of materials. This paper offers a thorough summary of how these ions' unique f-orbitals allow for a variety of innovative applications, especially in the areas of energy storage, corrosion prevention, and smart sensing. After providing an overview of the synthesis processes of Ln-MOFs, which frequently involve solvothermal or hydrothermal methods, the paper provides a detailed account of their complex structures, emphasizing their large surface areas, high porosity, and adjustable frameworks. The coordination chemistry basics of these MOFs are covered in considerable detail, highlighting the vital function of the f-orbitals, which are protected from outside ligands and environments and maintain the inherent characteristics of the lanthanide ions. Their multifunctional capabilities are largely due to the persistent magnetic moments and bright, distinctive luminescence spectra that result from this shielding. The review's main focus is on the various uses of MOFs based on lanthanides. Since their porous nature allows them to incorporate corrosion inhibitors for on-demand release, lanthanide structures are being considered as possible protective coatings or self-healing systems for corrosion protection. The article looks at how they are used in energy storage in supercapacitors and batteries, where their large surface area and structural stability allow for dependable cycling performance and quick ion diffusion. Lastly, the paper explores their application in smart sensing, where Ln-MOFs' special luminescence characteristics, specifically, their long luminescence lifetimes and narrow emission bands, make them perfect for highly sensitive and selective analyte detection. The purpose of this review is to provide insights for future materials science research and development by relating the advanced functionalities of Ln-MOFs to the basic coordination chemistry of lanthanides.