First-principles analysis of Ti3C2Tx MXene as a promising candidate for SF6 decomposition characteristic components sensor

Abstract SF6 decomposition characteristic components detection is currently one of the effective technical means for SF6 gas insulation equipment condition monitoring, and sensors are the key to achieving this goal. In this paper, two-dimensional MXene is used as a sensing material, combined with DFT method to study the adsorption behaviour of Ti3C2Tx with different termination groups (O, F, OH) on the main decomposition characteristic components of SF6 such as H2S, SO2, SOF2 and SO2F2.The most stable structure, α-model Ti3C2Tx was obtained and various gas adsorption structures were constructed and geometrically optimized. The most stable adsorption structures of different Ti3C2Tx surfaces were obtained by comparing the adsorption energy. The electron density, band structure and density of states of the adsorption system were further analyzed. The results show that target gases adsorb spontaneously on Ti3C2O2 and Ti3C2(OH)2, while on Ti3C2F2 external energy is required to form stable adsorption structures. Charge transfer induced by gas adsorption gradually decreases at the order of Ti3C2(OH)2, Ti3C2O2 and Ti3C2F2. Hydroxyl groups terminated Ti3C2Tx MXene performed better sensing ability over oxygen and fluorine terminated ones. And 2D Ti3C2(OH)2 is a promising candidate for SF6 decomposition characteristic components sensor, surpassing graphene and transition metal dichalcogenides.