A Novel Molybdenum Disulfide-Based High-Precision Microwave Sensor for Methanol Gas Detection at Room Temperature

This letter reports, for the first time, a molybdenum-disulfide (MoS $_2$ )-coated microwave gas sensor for methanol gas detection. A wideband monopole antenna, resonating at 2.45 GHz for wireless applications, is fit with a 15-mm-long copper-based grating sensing element for high-precision gas sensing. When the sensor surface is coated with a highly sensitive layer of hydrothermally grown MoS $_2$ and exposed to methanol gas, the electrical properties of the sensing material change. The developed sensor confirms the detection of methanol gas in parts per thousand (ppt) range from 5.3 to 42.6 ppt with a sensitivity of $\sim$ 1.0 MHz/5 ppt. Furthermore, the gas-sensing functionality of the sensor does not affect the communication performances of the antenna, suggesting seamless integration into wireless sensor networks (WSNs). The simulation results, experimental data, and sensing mechanisms are provided to support the claims.