Enhanced Electron Transport in 2D–2D Interface of Ti3C2Tx/SnS2 for Highly Selective Detection of Trimethylamine at Room Temperature

Efficient detection of toxic gases is essential for monitoring air quality and safeguarding human well-being and health. The performance of gas sensors is governed by the transport efficiency of charge carriers within the sensing material. Therefore, we propose a new strategy to enhance the electron transport in the selective detection of trimethylamine (TMA) at room temperature by a 2D–2D interface. It is demonstrated in an in–situ growth of SnS₂ nanosheets on a two–dimensional Ti₃C₂T_x surface by a facile one–step hydrothermal method with varying the amount of Ti₃C₂T_x. Electronic structure results proves that Ti₃C₂T_x and SnS₂ are well chemically bonded to each other via Ti–S covalent bonds in the 2D–2D interface. The detection of TMA facilitated by this interface has achieved a low theoretical detection limit (LOD for TMA = 73.58 ppb), excellent selectivity toward TMA, high reproducibility, and long–term stability (12.25% decrease in response after 30 days of operation), with a response value of 27.98% (10 ppm), 3.82 times higher than that of pure SnS₂ (7.33%, 10 ppm). The underlying mechanisms of the enhanced electron transfer and surface adsorption at the 2D–2D interface are elucidated through both experimental results and Density Functional Theory (DFT) simulations.