A high-performance H2 gas sensor based on PtOx and PdOy co-decorating WO3 film

As a form of clean energy, hydrogen (H2) offers significant potential to mitigate the effects of global warming caused by fossil fuels. The development of high-performance H2 gas sensors is crucial for monitoring its potential leaks. Previous studies have shown that noble metal Pt or its oxides (PtOx) can decrease the operating temperature of the H2 sensor but compromise selectivity. Conversely, noble metal oxide PdOy can enhance selectivity but tends to increase the operating temperature. Optimized co-decoration with these noble metal/metal oxides may simultaneously improve the selectivity and operating temperature of the sensor. Semiconductor film-based gas sensors, with their high compatibility with semiconductor device fabrication, are advantageous for miniaturization and integration. In this study, a high-performance H2 gas sensor was fabricated by co-decorating a WO3 film with dual noble metal oxides, PtOx and PdOy. This co-decoration strategy successfully decreased the operating temperature and enhanced the sensor's selectivity for H2. Under the optimal decoration ratio of Ptmolar : Pdmolar : Wmolar = 1.1 : 5 : 100, the sensor exhibited the best gas sensing performance. At an optimal operating temperature of 110 degrees C, the sensor demonstrated a detection limit of 200 ppb. Additionally, the sensor showed good selectivity, a linear response, robust batch-to-batch reproducibility, and long-term stability of up to 125 days. The sensor's high performance can be attributed to the densely packed WO3 nanoparticle film, the synergistic catalytic effects of PtOx and PdOy, and the heterojunctions formed between PtOx and WO3 as well as PdOy and WO3. With its relatively low operating temperature and high sensitivity, this sensor holds great promise for practical applications.