Microwave ultra-narrow band antenna sensor based on TiO₂/MXene for room-temperature acetone detection

Acetone sensors continue to command significant attention as a robust platform for emissions control, industrial safety monitor, and diagnostic analysis of human exhaled gas for diabetes monitoring. This study presents the design and fabrication of an ultra-narrowband, interdigital capacitor (IDC)-based three-level split ring resonator (TSRR) microwave gas sensor for rapid acetone detection. MXene-TiO₂ composites with varying mass ratios were deposited onto the resonator surface to evaluate the gas-sensitive properties of TiO₂/MXene materials across acetone concentrations of 10-500 ppm. Results demonstrate that the microwave acetone sensor incorporating the TiO₂/MXene (3 wt%) composite exhibits exceptional performance: high sensitivity (1544 mdB/ppm), rapid response and recovery durations (130 s and 140 s, respectively), superior selectivity, and excellent stability under high-humidity conditions - significantly surpassing existing microwave gas sensors. Furthermore, the gas-sensing mechanism was elucidated through impedance-matching circle diagrams corresponding to varying acetone concentrations. MXene materials, renowned for their expansive specific surface area, exhibit considerable promise in gas sensing applications, particularly for room-temperature acetone detection with high selectivity and sensitivity extending to ppb concentrations. This investigation introduces a novel paradigm for room-temperature acetone gas detection, as evidenced by the development of triboelectric plasma-regulated high-sensitivity sensors.