Pt-Doped HfS Monolayer as a Novel Sensor and Scavenger for Dissolved Gases (H, CO, CH, and CH) in Transformer Oil: A Density Functional Theory Study.

Detecting the types and concentrations of dissolved gases in insulating oil by resistivity-type sensors is an extremely effective means for diagnosing faults in an oil-immersed transformer. However, further breakthroughs and innovations are needed in gas-sensitive materials for preparing high-performance resistivity-type sensors. In this investigation, the application possibility of using Pt-doped HfS (Pt-HfS) as gas-sensitive materials for the detection of dissolved H, CO, CH, and CH in oil has been verified by analyzing the adsorption energy (), differential charge density (DCD), density of states (DOS), frontier molecular orbital, and desorption time based on density functional theory (DFT). The outcomes suggest that the band gap of HfS is obviously narrowed after doping Pt at the position of the bridge between the S and Hf atoms, resulting in a significant increase in the conductivity of HfS. The low adsorption energy implies that there is only weak physical adsorption between Pt-HfS and CO (-0.783 eV). In contrast, the highly hybridized atomic orbitals of Pt with H, CH, and CH indicate that strong chemical adsorption reactions occur. Two-dimensional Pt-HfS as a gas sensor has a great monitoring performance for CH at 298 K (room temperature). This research serves as theoretical guidelines for probing the application potential of Pt-HfS in fault diagnosis and predictive maintenance of an oil-immersed transformer.