Gas Sensing Mechanism and Adsorption Properties of CH and CO Molecules on the Ag-HfSe Monolayer: A First-Principle Study.

The detection of dissolved gases in oil is an important method for the analysis of transformer fault diagnosis. In this article, the potential-doped structure of the Ag cluster on the HfSe monolayer and adsorption behavior of CO and CH upon Ag-HfSe were studied theoretically. Herein, the binding energy, adsorption energy, band structure, density of state (DOS), partial density of state (PDOS), Mulliken charge analysis, and frontier molecular orbital were investigated. The results showed that the adsorption effect on CH is stronger than that on CO. The electrical sensitivity and anti-interference were studied based on the bandgap and adsorption energy of gases. In particular, there is an increase of 55.49% in the electrical sensitivity of CH after the adsorption. Compared to the adsorption energy of different gases, it was found that only the adsorption of the CH system is chemisorption, while that of the others is physisorption. It illustrates the great anti-interference in the detection of CH. Therefore, the study explored the potential of HfSe-modified materials for sensing and detecting CO and CH to estimate the working state of power transformers.