Oil-immersed transformers are essential components for voltage transformation and energy delivery within power systems, with their operating condition having a direct influence on the reliability and stability of the grid. During prolonged operation, multiple stresses─electrical, thermal, and mechanical─gradually degrade insulating oil and solid insulating materials, generating dissolved gases (H2, CH4, C2H2, C2H4). Monitoring the types and concentrations of these characteristic gases enables timely identification and condition evaluation of internal faults in transformers. MoTe2 shows broad application prospects in gas sensing. However, its intrinsic structure exhibits limited adsorption capacity for these four gas molecules. To enhance its sensing performance, this work systematically explored how transition metal (Au, Ir, Pd, Ti) doping influences the properties of single-layer MoTe2 in detecting transformer fault characteristic gases, using first-principles density functional theory (DFT). Structural stability was evaluated through binding energy calculations, while adsorption mechanisms were analyzed using adsorption energy, charge transfer, and density of states (DOS) studies. The findings reveal that introducing metal dopants markedly improves MoTe2's ability to adsorb and its electronic response characteristics toward gas molecules. Specifically, Au-MoTe2 exhibited recovery times of 0.44 and 2.15 s for detecting C2H2 and C2H4, respectively, and demonstrated a significant bandgap modulation effect, while Ti-MoTe2 exhibited substantial bandgap shifts (-18.9% and -462.21%) during H2 and CH4 detection, demonstrating high sensitivity and responsiveness. All demonstrate tremendous potential as gas-sensitive materials for their respective gases. This work elucidates the modulation mechanism of transition metal doping in MoTe2, providing theoretical guidance for designing high-performance materials for dissolved gas detection in transformer oil.
Jia et al. (Tue,) studied this question.