Broadband Dielectric Spectroscopic Detection of Aliphatic Alcohol Vapors with Surface-Mounted HKUST-1 MOFs as Sensing Media

Abstract

We leveraged chemical-induced changes to microwave signal propagation characteristics (i.e., S-parameters) to characterize the detection of aliphatic alcohol (methanol, ethanol, and 2-propanol) vapors using TCNQ-doped HKUST-1 metal-organic-framework films as the sensing material, at temperatures under 100 °C. We show that the sensitivity of aliphatic alcohol detection depends on the oxidation potential of the analyte, and the impedance of the detection setup depends on the analyte-loading of the sensing medium. The microwaves-based detection technique can also afford new mechanistic insights into VOC detection, with surface-anchored metal-organic frameworks (SURMOFs), which is inaccessible with the traditional coulometric (i.e., resistance-based) measurements.

Metal-organic-framework-based materials as green catalysts for alcohol oxidation

“…Alcohol adsorption and transformation of alcohol into carbonyl compounds induced by MOF metal nodes would result in permittivity changes and interfacial polarization of the materials, which could be easily detected by microwave energy dissipation. However, the main focus of this work was alcohol detection, which only confirmed that the synthesized catalyst could be used for the electrooxidation of alcohol; the specific catalytic performance parameter was unknown [170].…”