Understanding proton conduction enhancement of MOF-802 through in situ incorporation of imidazole into its channels

In this study, the proton-conducting properties of zirconium-based MOF-802 were investigated. MOF-802 exhibited remarkable thermal, aqueous, and acidic stabilities as well as room temperature superprotonic conduction under 98% relative humidity (RH), however, the proton conduction sharply drops above 318 K due to the release of lattice water molecules. To address this issue, a facile one-pot synthetic method was developed to encapsulate high boiling imidazole molecules in the pores/channels of MOF-802 as proton-transport medium, resulting in Im@MOF-802-S, which showed the enhanced proton conduction regarding MOF-802. We conducted a detailed discussion on the factors contributing to the improvement of the proton-conducting nature of MOF-802.