Mechanism analysis of PtPd-decorated hexagonal WO3 nanorods for H2S sensing application with ppt-level detection limit

Compared with single metal modification, bimetal modification shows good gas sensing properties, but it should be further improved in terms of detection limit. In this work, the hexagonal WO3 (h-WO3) nanorods with Pt and Pd co-modification were synthesized via a simple method. The [email protected]h-WO3 sensor has better gas sensitivity and selectivity to H2S gas. The response is 196.188 to 10 ppm H2S at 120 °C, which is 49.47 times that of the original h-WO3 (3.966). And the detection limit of the [email protected]3 sensor can reach the ppt level (as low as 506 ppt). The morphology of the composite material is characterized by SEM, TEM and HRTEM. The gas-sensing mechanism is carefully researched through XPS analysis. Compared with the pure h-WO3, the enhanced gas sensitivity of [email protected]h-WO3 sensor is mainly ascribed to the synergistic effect between Pt and Pd.