N-doped clay-like Ti3C2Tx MXene/N-doped CNTs composites for ethylene glycol detection in ambient air and exhaled breath

Abstract

Ethylene glycol is odorless and harmful to humans. Each year, a large number of fatal cases are caused by ethylene glycol poisoning. Therefore, rapid identification of ethylene glycol is crucial. In this study, clay-like Ti₃C₂T_x MXene exhibits a larger interlayer spacing compared to accordion-like Ti₃C₂T_x MXene, which enhances the gas diffusion channels. Nitrogen doping can increase the active sites of clay-like Ti₃C₂T_x MXene. The introduction of nitrogen-doped carbon nanotubes into N-Ti₃C₂T_x was carried out to enhance selectivity towards ethylene glycol, leading to the formation of N-Ti₃C₂T_x MXene/N-CNTs. The N-Ti₃C₂T_x MXene/N-CNTs exhibits significant selectivity towards the ethylene glycol at room temperature. Meanwhile, the detection limit was 0.3484 ppm, with a shortened response/recovery time of 10.57/6.29 s. Meanwhile, the ethylene glycol sensor device has been prepared through custom-made circuit boards and sensing programs. Moreover, the adsorption and oxidation process of ethylene glycol on N-Ti₃C₂T_x MXene/N-CNTs was explored through in-situ infrared spectroscopy testing. This study revealed that the oxygen vacancies on the surface of N-Ti₃C₂T_x MXene/N-CNTs play a crucial role in the oxidative catalytic detection of ethylene glycol. The strategy of N-Ti₃C₂T_x MXene/N-CNTs provides a new avenue for the detection of ethylene glycol.