Preparation of Pd/PdO loaded WO3 microspheres for H2S detection

Sensors based on pristine and Pd/PdO-loaded WO3 microspheres (NWs) were fabricated for H2S detection. Solvothermal method was employed to synthesize pristine WO3 microspheres. The Pd/PdO decoration procedure was realized by immersing the pristine WO3 into the solution with Pd precursor. Pd/PdO nanoparticles with diameter around 4 7 nm were successfully loaded on the surface of the WO3 microspheres characterized by SEM, TEM, HRTEM, EDS and XPS. Sensing performances were systematically investigated with varying Pd loading amount (0 at%, 1 at%, 2 at%, 5 at%). The sensitively and selectively were significantly improved after loaded with Pd. The 2 at % loaded sensing material exhibited the highest response of 1029 to 25 ppm H2S, which was 270 times higher than the pristine WO3 at 190 degrees C. Importantly, the sensor showed quite short response time (less than or equal to1 s) after loaded with Pd/PdO. The tremendous gas sensing enhancement could be attributed to the adjustment of the oxygen state, modulation of sensor resistance and catalytic effects of Pd/PdO. This study demonstrated that decorating WO3 with Pd/PdO is an effective route to realize the H2S detection with high response. The fabricated H2S sensor offered potential applications in the fields of rapid detection toward H2S.