Precious metal palladium (Pd) exhibits distinct adsorption and dissociation properties and electronic effects toward H2. However, its low concentration remains a challenge for achieving high-performance hydrogen detection. This study demonstrates the synthesis of a low-concentration Pd-loaded W18O49 heterostructure via sequential solvothermal and chemical reduction methods for low-temperature hydrogen sensing. The test results show that 0.6 wt% Pd/W18O49 has the highest response value to H2 (4.5@100 ppm). In addition, the 0.6 wt% Pd/W18O49 sensor also has good repeatability, linear relationship (R2=0.9968), and long-term stability for 40 days. DFT shows that compared with W18O49 (-0.08 eV), Pd/W18O49 (-0.44 eV) has a strong adsorption capacity for H2. The enhancement of gas sensing performance is mainly attributed to the synergistic effect of oxygen vacancies and Pd sensitization. This work provides a viable strategy for designing advanced H2 sensors offering dual advantages of low operating temperature and high sensitivity.
