Enhanced VOC Sensing Performance of Double Transition-Metal MXenes via Pulsed Laser Ablation in Liquid

MXenes are renowned for their exceptional chemical and physical properties, making them highly promising for gas sensing applications. However, instability remains a significant limitation for these materials. Compared with mono-transition-metal (MTM) MXenes, double transition-metal (DTM) MXenes theoretically offer higher stability and functional diversity. In this study, we fabricated a gas sensor based on DTM MXenes (VNbCT_x), which demonstrated excellent gas sensing performance toward volatile organic compounds (VOCs). More importantly, the sensor exhibited remarkable stability, with its performance declining by only 7% after it was stored in an atmospheric environment for 90 days. Moreover, by integrating characterization techniques with density functional theory calculations, it was demonstrated that the pulsed laser ablation in liquid (PLAL) strategy could alter the types of surface functional groups on MXenes while simultaneously increasing the number of material defects and edges. These modifications lead to an enhanced response of the sensors toward VOCs.