In this work, the adsorption of four types of SF6 decomposed products over the perfect and defective (containing one S or W vacancy) WS2 monolayer was theoretically investigated using the density functional theory (DFT). By calculating the adsorption energy, electron transfer and comparing the band structure and the density of states (DOS) before and after gas adsorption, the physical and chemical interactions can be evaluated. The results show that the adsorptions of gas molecule over the perfect are mainly physisorption with low possibility of new bond formation. In the present of S vacancy, the SO2 adsorption can repair the S vacancy with an energy barrier of 1.28 eV and also, the adsorption leads to the significant increase of the band gap and high possibility of new bond formation. The introduction of W vacancy could not increase the adsorption energy for all gas molecules. However, it enhances the electron transfer between the SO2/H2S and the WS2 monolayer. The larger electron transfer may lead to the higher response of strong n-type or p-type WS2 monolayer toward the detected gas molecule. This work may provide prospective insight into the future application of the defective WS2 monolayer as gas sensing device.

Double transition metal catalysts (DACs) can provide distinguished activity and low overpotential for CO₂ reduction to C₂ products.

We adopted density functional theory combined with non-equilibrium Green’s function to investigate monolayer PtSe ₂ ’s gas sensing properties and adsorption of five types of SF ₆ decompositions (SO ₂ , SOF ₂ , SO ₂ F ₂ , H ₂ S, and HF), and explore the response of a simulated monolayer PtSe ₂ -based device to these gases. We discussed the adsorption configurations, adsorption energy, electron transfer, electron localization function, density of states (DOS) including the chemical interactions, and the current–voltage property. These observations were relevant in studying the device response to different gas molecules. Changes in the molecule orbitals in DOS could approximately evaluate the chemical interactions among the gas molecules to a certain extent. Changing the bias voltage could adjust the response of the device to different gas molecules. Ultra-thin PtSe ₂ can be a promising gas sensing material in detecting SF ₆ decompositions.

The adsorption and gas sensing properties of monolayer MoS2 to five kinds of sulfur hexafluoride decompositions (SO2, SOF2, SO2F2, H2S, HF) were explored using density functional theory (DFT) combined with nonequilibrium Green’s function (NEGF). The adsorption energy, electron transfer, charge density difference (CDD) configurations, current-voltage (I-V) character using a two-electrode based device and transmission coefficient have been discussed. The results show that the adsorption of SO2 brings the largest adsorption energy as well as electron transfer. According to the simulated device, the unique negative conductance phenomenon was found for SO2. The MoS2 monolayer based sensor has the highest response to SO2 when the bias voltage is 1.2 V, reaching 7.74 and has the largest response to H2S when 1.8 V. The transmission spectrum analysis shows that after introducing different gas molecule, the transmission coefficient has different changes in different energy range. This work can provide theoretical basis for designing MoS2 monolayer based gas sensing device to detect the decompositions of sulfur hexafluoride or other specific gases.

TM–N₄ embedded b-PC can be a promising bifunctional catalyst for the ORR/OER.