Theoretical Study on Gas-Sensing Mechanisms of Transition Metal-Doped MoS<sub>2</sub> for Transformer Oil Dissolved Gases
Wenwen Jiang, Qingbin Zeng, Xiao Wei, Yujie Chen, Yiyi Zhang, Pengfei Jia
Abstract
Oil-immersed transformers are essential components in power transmission and distribution systems, and their insulation performance and operation status are closely related to the changes of dissolved gases in the internal oil. The use of high-performance gas-sensitive materials to realize online detection of dissolved gases in the oil is of great significance to enhance the reliability of equipment operation and fault detection. In this work, the adsorption behavior and sensing performance of four typical dissolved gases in transformer oil (H 2, CH 4, C 2 H 2, C 2 H 4 ) on the surface of MoS 2 doped with different transition metals (Cu, Ni, Ta, Ti) are systematically investigated based on the density functional theory (DFT). First, the analysis yielded poor sensing properties of pristine MoS 2 for four gas molecules. Then the most stable doping structure of TM–MoS 2 is selected, and based on this stable configuration, the adsorption structure was constructed and optimized. Comparative analysis of the structure, adsorption energy, charge transfer, density of states and work function parameters of TM–MoS 2 after adsorption of gas molecules showed that doping with transition metals can improve the adsorption and sensing properties of the material. Finally, the recovery time and sensitivity were investigated, and the results showed that Cu–MoS 2 exhibited suitable recovery time and high sensitivity in detecting C 2 H 2 and C 2 H 4, Ta–MoS 2 for CH 4 and Ti–MoS 2 for H 2 . This work provides theoretical guidance for the potential application of transition metal-doped MoS 2 as a gas-sensitive material in transformer fault gas detection.