Design of Electroactive Metal-Organic Framework-Based Thin Films via a Gel Precursor Method.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Electroactive metal-organic frameworks (MOFs) show promise for electrochemical devices.
• Traditional MOF thin-film electrode preparation uses binders, leading to homogeneity issues and performance compromise.
• Binder-free and scalable deposition techniques are needed for practical MOF applications.

Purpose of the Study:

• To develop a binder-free, scalable method for depositing electroactive MOF thin films.
• To engineer MOF electroactivity and tunable permselectivity using defects and redox shuttles.
• To demonstrate potential-stimuli electrochemical gating capabilities in MOF films.

Main Methods:

• Utilized a zirconium-based MOF gel (UIO-66) as a binder-free precursor ink.
• Employed drop-casting for homogeneous and conformal MOF thin film deposition with controllable thickness.
• Incorporated ferrocene redox-active shuttles into MOF pores, leveraging missing linker defects.
• Confirmed bias-induced permselectivity using scanning electrochemical microscopy.

Main Results:

• Successfully fabricated homogeneous, conformal, binder-free UIO-66 MOF thin films.
• Engineered electroactivity in MOF films by incorporating ferrocene redox shuttles.
• Demonstrated reversible, bias-controlled switching of film permselectivity.
• Showcased potential-stimuli electrochemical gating capabilities.

Conclusions:

• A binder-free MOF gel precursor enables scalable thin film deposition.
• Ferrocene incorporation and defect engineering yield electroactive MOFs with tunable gating.
• This approach facilitates the design of MOF-based films for regulating electrocatalytic reactions.