Arc-discharge-assembled CNT/MoO3 nanohybrids for ultra-sensitive and selective sub-ppm ethanol detection at room temperature.

In this study, one-dimensional carbon nanotube (CNT) and zero-dimensional MoO3 nanohybrids were synthesized using a simple arc-discharge method for ethanol gas sensor applications. MoO3 nanoparticles were uniformly distributed on the surface of mesoporous CNTs, which increased the specific surface area and the availability of active sites for charge carriers within the nanohybrid. MoO3 functions as the receptor, while the CNTs serve as the transducer, leading to the modification in the depletion region at the hybrid surface, followed by enhancement of the sensing performance. The CNT/MoO3 sensor exhibited the highest response of 76.5% to 1 ppm ethanol even at room temperature operation (30 °C), significantly outperforming CNT (12.5%) and MoO3 (2.5%). Additionally, the CNT/MoO3 sensor revealed rapid response and recovery time, excellent selectivity, and minimal humidity dependence. SEM, TEM, XRD, XPS, and BET analyses confirmed that the improved gas sensitivity of the CNT/MoO3 nanohybrid is attributed to the increased active sites for charge carriers, abundant surface vacancies, and modification in the depletion region.