Two-Dimensional Conductive Metal-Organic Framework for Small-Molecule Sensing in Aqueous Solution.

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• Two-dimensional conductive metal-organic frameworks (2D cMOFs) show promise as electrochemical sensing transducers.
• Electrochemical sensing applications of 2D cMOFs in aqueous solutions are currently underdeveloped.
• Interfacial capacitance has not been previously explored for 2D cMOF-based sensing in water.

Purpose of the Study:

• To develop a novel electrochemical sensing platform utilizing the interfacial capacitances of 2D cMOFs in aqueous media.
• To demonstrate the detection capabilities of this new platform for various analytes.
• To elucidate the underlying sensing mechanisms.

Main Methods:

• Utilized the interfacial capacitances of a 2D cMOF for electrochemical sensing in aqueous solutions.
• Detected both redox-innocent and redox-active compounds using capacitance peak responses at low voltages.
• Investigated the sensing mechanism through analysis of pseudocapacitance and ligand redox state transitions.

Main Results:

• Successfully detected various compounds in aqueous solutions using two distinct capacitance peaks.
• Achieved quantitative sensitivity to ascorbic acid that was an order of magnitude higher than prior voltammetric methods.
• Identified the sensing mechanism as originating from the pseudocapacitances of the 2D cMOF, involving ligand redox state changes.

Conclusions:

• The interfacial capacitance of 2D cMOFs can be effectively utilized for electrochemical sensing in aqueous solutions.
• The sensing mechanism involves analyte-induced alterations in d-p conjugation and electron exchange with the 2D cMOF.
• This work provides crucial insights into response mechanisms, advancing the application of 2D cMOFs in chemical sensing.