Superprotonic Conductivity of a UiO‐66 Framework Functionalized with Sulfonic Acid Groups by Facile Postsynthetic Oxidation

Abstract Facile postsynthetic oxidation of the thiol‐laced UiO‐66‐type framework UiO‐66(SH) 2 enabled the generation of UiO‐66(SO 3 H) 2 with sulfonic acid groups covalently linked to the backbone of the system. The oxidized material exhibited a superprotonic conductivity of 8.4×10 −2 S cm −1 at 80 °C and 90 % relative humidity, and long‐term stability of the conductivity was observed. This level of conductivity exceeds that of any proton‐conducting MOF reported to date and is equivalent to the conductivity of the most effective known electrolyte, Nafion.