Synergistic effects of bimetallic Pd-Au(alloy)/SnO₂ nanocomposites for low temperature and selective hydrogen gas sensors

In view of the explosive nature of hydrogen gas, the demand for detection is increasing. Although Pd-based chemiresistive sensors are gaining much attention in hydrogen detection, it is easily oxidized at high temperatures, leading to the deterioration of sensing performance. To address this issue, we synthesized bimetallic Pd-Au alloy nanoparticles (NPs) and mixed them with SnO₂ powder for improving the hydrogen sensing performance. The response of the bimetallic Pd-Au(alloy)/SnO₂ nanocomposites (NCs) sensor toward 100 ppm hydrogen was 72.78 which is 7 times higher than that of the pure SnO₂ sensor at a relatively lower working temperature of 150°C. Furthermore, when compared to other interfering gases, the sensor revealed high selectivity for hydrogen gas. The enhanced hydrogen sensing performance was attributed to the synergistic effect arising from the formation of a heterojunction interface between Pd-Au alloy and SnO₂ NPs and the decomposition and absorption of hydrogen molecules by Pd-Au alloy NPs.