Hydrogen Sensing Properties of Pure and Pd Activated WO₃ Nanostructured Films

Pure and Pd‐doped WO₃ Nanocrystalline tungsten oxide films on alumina substrates were prepared via sol‐gel method from peroxopolytungstic acid. AFM, XRD, SEM, XPS methods were used to determine the surface morphology, grain size and layer composition. XRD analysis showed WO₃ nanocrystalline particles in monoclinic phase and with average size of about 33±3 nm, which was consistent with SEM analysis results. Sensing properties of samples toward H₂ gas was studied. The sensitivity of WO₃ nanocrystalline films was about 4 at 2300 ppm (0.2%) H₂ gas. Introducing Pd to the system led to an increase in the sensitivity about 2 orders of magnitude. The sensitivity of Pd: WO₃ was about 400 at 2300 ppm H₂.

Keywords:

• gas sensor‐nanostructures‐WO₃