Effect of Missing-Linker Defects and Ion Exchange on Stability and Proton Conduction of a Sulfonated Layered Zr-MOF

Intentionally introduced defects into solid materials create opportunities to control and tune their diverse physicochemical properties. Despite the growing interest in defect-engineered metal-organic frameworks (MOFs), there are still only a handful of studies on defective proton-conducting MOFs, including no reports on two-dimensional ones. Ion-conducting materials are fundamentally of great importance to the development of energy storage and conversion devices, including fuel cells and batteries. In this work, we demonstrate the introduction of missing-linker defects into a sulfonated proton conductive 2D zirconium-based MOF (JUK-14), using a facile post-synthetic approach and compare the stability and performance of the resulting materials, including proton conductivity, as well as adsorption of N₂, CO₂, and H₂O molecules. We also discuss the associated presence of interlayer counterions and their effect on the properties and stability. Our approach to defect engineering can be extended to other layered MOFs and used for tuning their activity.