Pd-GaSe and Pd3-GaSe Monolayers: Two Promising Candidates for Detecting Dissolved Gases in Transformer Oil

Abstract

In this paper, the adsorption behaviors of three gases (H2, CO, and C2H2) decomposed by the transformer oil on Pd-GaSe and Pd3-GaSe monolayers were calculated by density functional theory. Compared with Pd single-atom doping, Pd3 cluster doping changed the original structure and charge distribution to a greater extent, and more obviously improved the conductivity. According to the analysis of adsorption energy, charge transfer and deformation charge density, the results show that the two doped structures have better adsorption performance for the three gas molecules (H2, CO, and C2H2) than the intrinsic GaSe monolayer. Compared with Pd-GaSe, Pd3-GaSe showed stronger adsorption property for the three gases. Analysis of frontier molecular orbitals and recovery characteristics shows that Pd3-GaSe can be used as an ideal gas sensitive material for H2 detection because of its good desorption properties and obvious conductivity changes. Pd-GaSe can be used as a disposable resistive sensor for CO. Pd3-GaSe is a kind of sensing material suitable for disposable resistance sensors for CO and C2H2. These two doped structures have great application potential in gas adsorption and detection, and provide indications for further study on gas sensor detection by means of metal-doped GaSe monolayer.