Enhancing the NO2 detection ability of surface acoustic wave sensors with ZnO-decorated N-doped porous carbon nanosheets†

Effective detection of nitrogen dioxide (NO₂) is crucial for environmental safety and human health. Gas sensors utilizing surface acoustic wave (SAW) technology hold significant promise for detecting hazardous gases, but their performance heavily depends on the intrinsic properties of the sensing layer materials. In this study, we elaborate on using ZnO nanoparticle-dispersed N-doped porous carbon nanosheets (ZnO@N-PCNs) for SAW sensors aimed at achieving rapid NO₂ detection at room temperature. The resultant ZnO@N-PCNs SAW gas sensor exhibits a significant frequency shift of approximately −4.4 kHz, which is much higher than that of the pristine N-PCNs SAW sensor at a NO₂ concentration of 20 ppm. It responds quickly when exposed to NO₂ gas, and demonstrates specific selectivity and good reproducibility over both short and long terms. This work reveals the sensing properties of ZnO-optimized SAW sensors and provides valuable guidance for the development of high-sensitivity SAW sensors.