Optimizing coverage of palladium nanoparticles for a highly sensitive hydrogen gas sensor based on nanogaps via spray-deposition

The Hydrogen (H₂) sensor based on palladium nanogaps (Pd NGs) offers the advantages of low detection limits and fast response times. It holds significant potential for early warning of H₂ leakages. However, the preparation methods of Pd NGs for such sensors are really complex. In this study, the spray-deposition method was introduced to streamline the preparation method of Pd NGs and optimize the quantity of Pd NGs by adjusting the coverage of Pd nanoparticles (Pd NPs). The effect of different coverage of Pd NPs on the gas sensing performance of the sensor was investigated. The results revealed that sensors with lower coverage exhibited higher H₂ sensitivity. The sensor exhibited a response time of 10 s at room temperature and shorten to 2 s at 100 °C in 2500 ppm H₂. Furthermore, the sensor achieved a detection limit as low as 50 ppm. These findings offer a method for effectively optimizing the sensing performance of Pd NGs based H₂ sensors.