Room Temperature VOCs Sensing with Termination‐Modified Ti3C2Tx MXene for Wearable Exhaled Breath Monitoring

Abstract Room temperature volatile organic compounds (VOCs) sensors usually suffer from severe humidity interference and insufficient sensitivity against VOCs, which greatly restricts its practical applications. Herein, the authors simultaneously reduce the hydrophilicity while improving the VOCs sensitivity of Ti 3 C 2 T x MXene by introducing hydrocarbon terminations. The termination‐modified Ti 3 C 2 T x (Ti 3 C 2 T x ‐M2) sensor demonstrates fivefold enhancement in ethanol sensitivity at room temperature, while response against water vapor has been reduced by 71% compared with pristine Ti 3 C 2 T x . In addition, the modification also contributes to the arrest of sensor degradation that refines the sensing stability. On this basis, the MXene‐based VOCs sensor is employed for in situ, real‐time monitoring of exhaled ethanol as a proof‐of‐concept by integrating it with a wearable detection tag. Owing to the suppressed humidity interference and amplified VOCs response, the Ti 3 C 2 T x ‐M2 sensor could dynamically track the exhaled ethanol variations after alcohol intake. This work not only demonstrates a facile modification strategy to promote the sensitivities of MXene‐based VOCs sensor, but also a promising scheme for facile breath analysis, shedding lights on MXene‐based wearable medical electronics and intelligent healthcare.