First-principles insight into a Nb-embedded PdSe2 monolayer for dissolved gas sensing in oil-immersed transformers of a regional power grid

Abstract

As the integration of renewable energy into the regional urban power grid, guaranteeing the safety of oil-immersed transformers emerges as a top priority. Dissolved gas analysis by nanomaterial-based gas sensor is a workable technique to evaluate the operation status of the oil-immersed transformers. This work purposes Nb-embedded PdSe2 (Nb-PdSe2) monolayer as a potential gas sensor upon C2H2 and C2H4, two typical dissolved gases, using the first-principles theory. One Se atom of the pristine PdSe2 monolayer is substituted by one Nb atom to establish the Nb-PdSe2 configuration, which is spontaneous at room temperature with binding energy of −1.81 eV. The adsorption characteristic of Nb-PdSe2 monolayer upon two gas species is analyzed and compared with other metal-doped TMDs. The analysis of electronic property reveals the favorable change in the bandgap of Nb-PdSe2 monolayer as well as the Nb-C bonding nature, leading to the strong sensing response of −99.99% and −99.87% in C2H2 and C2H4 systems using the frontier molecular orbital theory. These findings uncover the strong potential of Nb-PdSe2 monolayer as a resistive gas sensor upon two gases, which would be helpful to explore novel PdSe2-based gas sensor for application in some other fields.