Proton Conduction in Zirconium-Based Metal-Organic Frameworks for Advanced Applications

Abstract

Zirconium-based metal-organic frameworks (Zr-MOFs) have emerged as a promising class of crystalline porous materials, attracting significant interest in the field of proton conduction due to their exceptional chemical stability, structural flexibility, and functional tunability. Notably, proton-conducting Zr-MOFs show immense potential for diverse advanced technological applications. In this Spotlight on Applications paper, we provide an overview of proton-conducting Zr-MOFs and spotlight the recent progress of their utilization as proton exchange membranes in proton exchange membrane fuel cells (PEMFCs), light-responsive systems for proton pumps, and chemical sensors for formic acid detection. Furthermore, we also discussed the challenges, future prospects, and opportunities for promoting the application of proton-conducting Zr-MOFs.

Figure 1

Schematic illustration of strategies for designing Zr-MOFs with proton conduction.

Figure 2

(a) Schematic illustrating the construction of MOF-808. (b) Optical images of the pure PVDF membrane and MOF-808@PVDF composite membranes. Reprinted with permission from ref (72). Copyright 2017 American Chemical Society. (c) Temperature-dependent proton conductivity and (d) the corresponding Arrhenius plots for MOF-808@PVDF composite membranes. Reprinted with permission from ref (72). Copyright 2017 American Chemical Society.

Figure 3

(a) Schematic illustrating the construction of MOF-801. (b) Temperature-dependent proton conductivity and (c) the corresponding Arrhenius plots for MOF-801@PP composite membranes. Reprinted with permission from ref (69). Copyright 2018 American Chemical Society. (d) The plot of open-circuit voltage versus time. (e) Polarization and power density curves of PEMFC prototype fabricated with MOF-801@PP-60 at 303 K and 100% RH. Reprinted with permission from ref (69). Copyright 2018 American Chemical Society.

Figure 4

(a) Schematic illustration of the preparation of MOF-808-AZOA via solvent-assisted ligand incorporation (SALI). The inset shows the optical photographs of MOF-808 and MOF-808-AZOA. Reprinted with permission from ref (115). Copyright 2024 American Chemical Society. (b) Cycling impedance response of MOF-808-AZOA with and without 365 nm UV light irradiation. Reprinted with permission from ref (115). Copyright 2024 American Chemical Society. (c) Switchable resistance of MOF-808-AZOA with and without 365 nm UV light irradiation. Reprinted with permission from ref (115). Copyright 2024 American Chemical Society.

Figure 5

Molecular simulations on a single large pore structure of MOF-808 bearing an AZOA group in either the trans- (a) or cis- (b) configuration. The atoms are colored in plum (Zr), gray (C), red (O), blue (N), and green (H). Reprinted with permission from ref (115). Copyright 2024 American Chemical Society.

Figure 6

(a) Schematic illustration of MOF-802 thin film sensor for formic acid sensing. Reprinted with permission from ref (146). Copyright 2021 American Chemical Society. (b) Response–recovery time curve of MOF-802 thin film sensor toward 3.2 × 10^–4 mol/L formic acid vapor. Reprinted with permission from ref (146). Copyright 2021 American Chemical Society. (c) Response of MOF-802 thin film sensor upon exposure to different chemical vapors. Reprinted with permission from ref (146). Copyright 2021 American Chemical Society. (d) Reproducibility cycles of MOF-802 thin film sensor toward 3.2 × 10^–4 mol/L formic acid vapor. Reprinted with permission from ref (146). Copyright 2021 American Chemical Society.

Figure 7

(a) SEM images of MOF-801 thin films. Reprinted with permission from ref (148). Copyright 2023 Elsevier. (b) Response of MOF-801 thin film sensor to formic acid with different concentrations. Reprinted with permission from ref (148). Copyright 2023 Elsevier. (c) Response–recovery time curve and (d) reproducibility cycles of MOF-801 thin film sensor to formic acid with a concentration of 3.2 × 10^–4 mol/L. Reprinted with permission from ref (148). Copyright 2023 Elsevier.