Partially Reduced and Stabilized Phase-Changed MoS₂ Hybrids for Vapor Molecular Absorption at Defects in Edge Sites

Current research in gas sensor technology emphasizes developing high-performance, miniaturized devices that operate at room temperature. Among emerging materials, molybdenum disulfide (MoS₂), a layered semiconductor, has garnered significant attention for its ability to detect diverse analytes with a high surface to volume ratio. In this study, composites of 1T and 2H MoS₂ with reduced graphene oxide (rGO) were synthesized, combining distinct physical and chemical properties that enable unique interactions with gas molecules. The applied synthesis routes are cost effective, reproducible, and readily compatible with field effect transistor printed devices. Sensor performance for nitric oxide (NO), nitrogen dioxide (NO₂), and ammonia (NH₃) gases in 1T-based hybrids was superior to that in 2H-based hybrids, which was attributed to the metallic and hydrophilic nature of the 1T phase. The hybrids displayed excellent performance across a wide concentration ranging from 500 ppb to 2 ppm. Notably, for NO detection, the 1T MoS₂@rGO sensor achieved responses of 5.4% at 500 ppb and 38.1% at 2 ppm. Density functional theory further confirmed the metallic character of the 1T phase. These results underscore the promise of phase-engineered MoS₂@rGO hybrids as next-generation materials for reliable room temperature gas sensing technologies.