Construction of biomimetic proton transport channels in metal-organic framework

Construction of proton transport channels in metal-organic frameworks (MOFs) with simple synthesis processes, high proton conductivities and good performance stabilities has been of great interest for proton exchange membrane fuel cell (PEMFC). Herein, we mimic the proton transport behavior of amino acid residues in bacteriorhodopsin, select UiO-66-COOH as the host, glycine and aspartic acid as the functional guest molecules, and then functionalize the MOF framework with amino acids to obtain biomimetic proton transport channels. This strategy endows UiO-66-COOH-Asp a high proton conductivity of 1.19 × 10−2 S/cm at 70 °C and 98% RH, excellent cycle stability of performances and performance durability, which can be comparable to the reported MOFs-based proton conductors. Moreover, the proton conduction mechanism in UiO-66-COOH-Asp is elaborated in detail due to its visual structure, which is also one of the advantages of adopting MOFs as research platform, making it possible to optimize the structure-activity relationship of advanced materials. Notably, this strategy has clear objectives and simple synthesis, which has made certain contributions to both theoretical research and future industrial production of proton conductors.