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. Decorated for honorable conductivity: The postsynthetic oxidation of a thiol-laced UiO-66-type framework generated sulfonic acid groups covalently linked to the backbone of the system (see picture; green circles are Zrpound;O nodes). The oxidized material exhibited stable superprotonic conductivity of 8.4×10 -2 S cm -1 at 80 °C and 90 % relative humidity.