Room-temperature surface acoustic wave gas sensor functionalized by Pt-doped ZnO nanomaterials for isopropanol detection

Non-invasive monitoring of exhaled isopropanol (IPA) is a promising route for diabetes management. However, current analytical methods are limited by inadequate sensitivity, low selectivity, and slow response times. In this work, we report a high-performance surface acoustic wave (SAW) gas sensor engineered with Pt-doped ZnO nanoparticle films synthesized via hydrothermal growth and spin-coating. The sensitive layer is optimized with 0.5 wt% Pt doping level, which enhances the specific surface area and pore structure uniformity. At room temperature (25°C), the sensor demonstrates exceptional performance, featuring highly selective IPA detection with a sensitivity of 6.76 Hz/ppm, fast response/recovery times of 12 s/12 s, a low detection limit of 1.38 ppm, and excellent reproducibility over 30 days of operation. Mechanistic studies confirm that the high selectivity is governed by a Pt-O coordination effect that facilitates preferential IPA adsorption. This work presents a robust and practical platform for diabetes monitoring and provides a clear strategy for the rational design of next-generation metal oxide-based gas sensors.