Proton-conducting lanthanide metal-organic frameworks: A platform for multifunctionality

Abstract

Lanthanide metal-organic frameworks (LMOFs) have established themselves as a promising proton-conducting material among all types of porous coordination polymers and covalent organic frameworks. The structural diversity of LMOFs and high oxophilicity with a high coordination number of lanthanide ions make the LMOFs a standout material for proton conductivity. Ample research effort has been devoted for the last few years to designing and developing proton-conducting lanthanide metal-organic frameworks (PCLMOFs). Some of the PCLMOFs have shown great potential with proton conductivity comparable to commercially used perfluorosulfonic acids (PFSAs) polymers for proton-exchange membrane (PEM) in fuel cells. Now it is also apparent that PCLMOFs are becoming a potential platform to explore other functional properties (e.g. fluorescence sensing, gas adsorption, molecular magnetism, impedance sensing, ferroelectricity, and nonlinear optics). The intrinsic structural features of PCLMOFs inevitably bring the opportunity to introduce the multifunctional character of such materials. So, any scope for additional functional property must be investigated for this class of material. In this article, we have concisely discussed the design strategy and structural features of some multifunctional PCLMOFs. The multifunctional properties of some excellent PCLMOFs are reviewed. In addition, the prospect of PCLMOFs is briefly discussed in the context of real-world material applications.