Ti₃C₂T_x as a Sensor for SF₆/N₂ Nitrogen-Containing Fault Decomposition Characteristic Products: A Theoretical Study

The SF₆/N₂ gas mixture is an alternative gas to SF₆. SF₆/N₂ will decompose and generate nitrogenous characteristic gases, such as NO, NO₂, N₂O, and NF₃, when exposed to long-term partial discharge. The adsorption models of Ti₃C₂T_x (T=O, F, OH) and NO, NO₂, N₂O, NF₃ were constructed, and the most stable adsorption structure was selected in this paper. The electron density and density of states of the adsorption system were further analyzed to study the adsorption behavior, and the sensing performance was evaluated in the end. The results are as follows: four gases could be spontaneously adsorbed on Ti₃C₂T_x, and strong adsorption occurred when surface terminal groups were OH, forming hydrogen or chemical bonds with significant charge transfer. Results show that Ti₃C₂(OH)₂ had a stronger sensing ability than Ti₃C₂F₂ and Ti₃C₂O₂. The conductivity of the Ti₃C₂T_x with different terminal groups was improved after the adsorption of NO and NO₂, showing Ti₃C₂T_x had a good sensing ability for NO and NO₂. It was difficult for the four gases to desorb from the Ti₃C₂(OH)₂ surface, but the adsorption on the Ti₃C₂F₂, Ti₃C₂O₂ surface had a short recovery time at room temperature.