Surface and Interface Investigation on MoS₂-rGO Hybrids for Room Temperature Gas Sensing

Novel resistive copper PCB-based sensors have been developed for room temperature NH3 gas detection at a concentration as low as 10 parts per million (ppm), employing a binary hybrid composition of molybdenum disulfide (MoS2) and reduced graphene oxide (rGO). These sensors utilize hierarchical structures that outperform unary MoS2 counterparts, with a 45% enhancement in sensing response at 10-ppm NH3 concentration. Surface analysis studies reveal surface charges and electronic interaction at the surface interface. The mentioned studies clarify gas–surface interactions, guiding material design for optimized response and sensitivity in gas sensing. It validates sensor performance, enhances understanding, and refines designs for practical applications. Notably, the interface and surface of hybrids have been thoroughly analyzed by X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET), respectively, enhancing our understanding of the structural and chemical aspects driving the enhanced sensing performance. This increase in sensitivity is underpinned by nanoscale electronic modifications at interfaces, particularly within nano heterojunctions, which not only amplify adsorption but also boost selectivity. The binary hybrid device, showcasing superior NH3 detection and specificity over volatile gases such as methanol, ethanol, isopropyl alcohol, and toxic carbon monoxide gas, emerges as a robust candidate for selective gas sensing. In addition, the foundation of these advancements is fortified by incorporating theoretical surface potential (SP) calculations, underscoring a significant stride toward the advancement of room temperature gas sensing technology.