Exploration of Pt-doped Janus WSSe monolayer as a typical gas sensor for condition assessment in XLPE cables

To evaluate the operation status of the XLPE cables in the power system, we purpose Pt-doped WSSe (Pt-WSSe) monolayer as a novel gas sensor for detections of the XPLE typical gases under the insulation defects. The adsorption and sensing mechanisms of the Pt-WSSe monolayer upon five typical gases, namely CO, C2H6, C2H4O, C4H6O and C8H8O are uncovered in this work, using the first-principles theory. We find that the for Pt-doping on Se-surface of the Janus WSSe monolayer is more energy-favorable and chemical stable, with the formation energy of −0.29 eV, and the bandgap of the identified Pt-WSSe monolayer is obtained as 1.34 eV. Besides, the Pt-WSSe monolayer performs chemisorption upon CO, C2H4O, C4H6O and C8H8O molecules, while performs physisorption upon C2H6 molecule, and the adsorption energies are calculated as −1.88, −0.97, −0.77, −1.55 and −1.62 eV, respectively. These gas interactions deform the electronic property of the Pt-WSSe monolayer, causing the remarkably change in its bandgap, and the caused sensing responses indicate the strong potential to be a potential resistance-type gas sensor upon CO, C2H4O and C4H6O detections, with the sensing response of −93.4 %, −97.5 % and −99.7 %, respectively. Moreover, the limited change in the work function (WF) of Pt-WSSe monolayer suggests its unsuitability to be a WF-type gas sensor for detection of XLPE typical gas species. All these findings not only illustrate the Pt-doping behavior on the physicochemical properties of Janus WSSe monolayer, but also uncover the gas sensing mechanism of metal-doped Janus TMDs for explorations of novel sensing materials.