Adsorption and sensing properties of SF₆ decomposed gases on Mg-MOF-74

Using the framework of density functional theory (DFT), this work investigated the adsorption properties of SF₆ decomposed H₂S, SO₂, SOF₂, and SO₂F₂ gases on a magnesium-based metal-organic framework (Mg-MOF-74). Further, the possible application of this MOF as a suitable sensor for the detection of these gas molecules is discussed through the analysis of adsorption energies, electronic properties, charge transfer, selectivity and sensitivity features and recovery time. The study revealed that the SO₂ molecule possesses relatively high adsorption energy (−1.26 eV) compared to H₂S (−0.10 eV), SOF₂ (−0.08 eV), and SO₂F₂ (−0.04 eV) molecules. Results show that all the molecules are physisorbed on the semiconducting Mg-MOF-74 and the adsorption energy has a strong correlation with the electronic properties. This reflects in the bandgap and the density of states analysis shows that the adsorption of H₂S, SOF₂, and SO₂F₂ molecules leads to insignificant changes in the bandgap, whereas the adsorption of SO₂ reduces the bandgap by almost 50%. The recovery time analysis also ensures that Mg-MOF-74 has a fast desorption ability for H₂S, SOF₂, and SO₂F₂ molecules, suitable for resistive and reusable chemical sensors for industrial applications.