An advanced performance preservation method for surface acoustic wave hydrogen sensors based on graphene sensitive layers

Abstract

High-performance hydrogen sensors are essential for efficiently utilizing hydrogen energy. We developed a high-performance surface acoustic wave sensor hydrogen sensor by integrating the advantages of surface acoustic wave technology (high sensitivity, compact structure, easy integration) with the properties of graphene-based materials. The sensor uses reduced graphene oxide, synthesized by a chemical redox method, as the sensitive film on a lithium niobate piezoelectric substrate, with platinum acting as the catalyst. Graphene provides the sensing layer with its large specific surface area and excellent optical, mechanical, and electrical properties. The fabrication process of the sensitive layer was optimized to improve sensor performance. Results show the sensor responds excellently to hydrogen, achieving a high sensitivity of 0.276 kHz/ppm and a low detection limit of 2 ppm at room temperature. This performance surpasses that of conventional metal oxide sensors. However, a significant limitation is the rapid degradation of sensor performance over time, limiting its practical application. To address this limitation, we investigated the effect of environmental humidity on sensor stability. The results show the sensor retains its capability to detect low-concentration hydrogen even after six months of storage under high-humidity conditions.