This work reports on the fabrication of an advanced capacitive sensor based on a MFM-300 (In) MOF for the detection of SO₂ at room temperature. The sensor revealed remarkable SO₂ sensitivity down to 75 ppb with excellent stability and selectivity to other common gases/vapors.

A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH₂O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH₂O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance.

Membrane‐based separations offer great potential for more sustainable and economical natural gas upgrading. Systematic studies of CO₂/CH₄ separation over a wide range of temperatures from 65 °C (338 K) to as low as −40 °C (233 K) reveals a favorable separation mechanism toward CO₂ by incorporating Y‐fum‐fcu‐MOF as a filler in a 6FDA‐DAM polyimide membrane. Notably, the decrease of the temperature from 308 K down to 233 K affords an extremely high CO₂/CH₄ selectivity (≈130) for the hybrid Y‐fum‐fcu‐MOF/6FDA‐DAM membrane, about four‐fold enhancement, with an associated CO₂ permeability above 1000 barrers. At subambient temperatures, the pronounced CO₂/CH₄ diffusion selectivity dominates the high permeation selectivity, and the enhanced CO₂ solubility promotes high CO₂ permeability. The differences in adsorption enthalpy and activation enthalpy for diffusion between CO₂ and CH₄ produce the observed favorable CO₂ permeation versus CH₄. Insights into opportunities for using mixed‐matrix membrane‐based natural gas separations at extreme conditions are provided.