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

Abstract

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 (PtO_x) can decrease the operating temperature of the H₂ sensor but compromise selectivity. Conversely, noble metal oxide PdO_y can enhance selectivity but tends to increase the operating temperature. Optimized co-decoration with these noble metal/metal oxides may simultaneously improve 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, PtO_x and PdO_y. This co-decoration strategy successfully decreased the operating temperature and enhanced the sensor’s selectivity for H₂. Under the optimal decoration ratio of Pt_molar : Pd_molar : W_molar = 1.1 : 5 : 100, the sensor exhibited the best gas sensing performance. At an optimal operating temperature of 110 °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 PtO_x and PdO_y, and the heterojunctions formed between PtO_x and WO₃ as well as PdO_y and WO₃. With its relatively low operating temperature and high sensitivity, this sensor holds great promise for practical applications.