Novel gas sensing mechanisms of Pd and Rh-doped h-BN monolayers for detecting dissolved gases (H2、CH4、and C2H4) in transformer oil.

Detecting dissolved gases in transformer oil is crucial for assessing the operational status of transformers. The gas composition in transformer oil can reflect the health status of the equipment and help identify potential failure risks in a timely manner. Based on density functional theory (DFT), Pd and Rh atoms were doped into the h-BN monolayer, and the most stable adsorption structures for each were first explored. Then, the sensing performance of the Pd-doped and Rh-doped h-BN monolayers for H₂, CH₄, and C₂H₄ gases was analyzed. The results indicate that Pd-BN and Rh-BN exhibit enhanced sensitivity to H₂ and C₂H₄ gases compared to pristine h-BN. However, they show poor adsorption characteristics for CH₄. Both Pd-BN and Rh-BN demonstrate strong chemisorption for H₂ and C₂H₄. In contrast, CH₄ adsorption is predominantly physisorbed. The desorption time of H₂ from Pd-BN at 398 K is 164 s, reflecting its excellent desorption performance. Additionally, Pd-BN and Rh-BN monolayers exhibit exceptional C₂H₄ capture capabilities, with adsorption energies of -1.697 eV and -2.188 eV, respectively, indicating their potential as C₂H₄ gas adsorbents. These findings provide theoretical insights for selecting materials for dissolved gas detection in oil and lay the groundwork for the development of Pd-BN and Rh-BN-based gas sensors.