Semiconductor-based room-temperature (RT) gas sensors have been extensively studied due to their low power consumption, which is critical for sustainable Internet of Things (IoT) applications. Two-dimensional (2D) semiconductors with high surface activity are emerging as promising candidates for the assembly of RT gas sensors; however, they currently suffer from shortcomings such as low sensitivity and poor stability. Herein, we synthesized ultrathin Mo-doped niobium oxyphosphate (NbOPO4) nanosheets via a one-step hydrothermal method for RT gas sensing. The resulting sensors exhibit excellent performance toward isopropanol (IPA), including a high response (8.7 to 100 ppm IPA), wide working range (0.1–400 ppm), rapid response/recovery rates (55 s/41 s), an ultralow detection limit (6 ppb), outstanding selectivity, and excellent reproducibility (RSD < 5%). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reveals a new reaction pathway for RT IPA sensing, involving its oxidation to acetic acid rather than CO2. This exceptional performance is attributed to the abundant oxygen vacancies induced by Mo doping and the material’s ultrathin layered morphology. Capitalizing on the inherently low power consumption of RT operation, we further constructed a highly miniaturized electronic nose system (11 mm×16 mm×8 mm) that integrates the MNOP sensor with energy-efficient wireless circuitry, demonstrating its practical utility in real-time environmental monitoring and personal health protection. The system exhibits ultralow power consumption (~ 16.5 µW), deterministic wireless communication, and high reliability in multi‑node deployment, positioning it as a competitive solution for next‑generation IoT-enabled gas sensing networks.
Ma et al. (Fri,) studied this question.