Room-temperature ethylene glycol sensor based on cuprous oxide/MXene films

This study demonstrates a high-performance room-temperature ethylene glycol (EG) gas sensor using Cu₂O/MXene bilayer films on quartz crystal microbalance (QCM) substrates, addressing critical needs for industrial safety and environmental monitoring. The fabricated sensors were systematically characterized by XRD, FTIR, and FESEM, revealing that the Cu₂O/MXene bilayer configuration achieved exceptional performance with an ultra-low detection limit of 381 ppb, high sensitivity of 22.8 Hz/ppm, and excellent selectivity compared to individual Cu₂O, MXene, or their mixture films. The enhanced sensing capability originates from synergistic effects between p-type Cu₂O and conductive MXene, forming a Schottky junction that facilitates charge transfer and promotes EG adsorption through combined physisorption mechanisms involving hydrogen bonding with MXene's functional groups (OH, O, F) and interactions with oxygen species on Cu₂O nanoparticles. At 72 ppm EG concentration, the bilayer sensor exhibited 12.6-fold, 3.6-fold, and 2.34-fold higher response than pure Cu₂O, MXene alone, and their mixture film, respectively. While humidity tests showed a moderate ~ 15% response reduction at 60% RH, the Cu₂O/MXene bilayer maintained robust performance, establishing it as a cost-effective and reliable room-temperature sensing platform suitable for next-generation gas detection applications in challenging environments.