Theoretical Study of the Adsorption and Sensing Properties of Cr-Doped SnP 3 Monolayer for Dissolved Characteristic Gases in Oil

Dissolved gas analysis (DGA) is a vital method for the online detection of transformer operation state. The adsorption performance of a SnP monolayer modified by transition metal Cr regarding six characteristic gases (CO, C H , C H , CH , H , C H ) dissolved in oil was studied. The study reveals the relevant adsorption and gas-sensing response mechanisms through calculations of the adsorption energy, density of states, differential charge density, energy gap, and recovery time. The results display a considerable increase in the adsorption effect of the Cr-SnP monolayer on six gases. The CO, C H , and C H gases lead to chemical adsorption, and the CH , H , and C H gases lead to physical adsorption. Combined with the recovery time, the Cr-SnP monolayer has a strong adsorption effect on CO and C H gases at normal temperatures and even high temperatures, and the adsorption is stable. C H gas can be rapidly desorbed from the Cr-SnP monolayer at 398 K. Therefore, the Cr-SnP monolayer can be expected to serve as a CO and C H gas adsorbent and a resistive gas sensor for C H gas. This research offers a theoretical foundation for the development of the Cr-SnP monolayer in gas-sensitive materials.