Highly Sensitive H₂ Sensors Based on Pd- and PdO-Decorated TiO₂ Thin Films at Low-Temperature Operation

In this work, the low-temperature H 2 -sensing properties of palladium (Pd) and palladium oxide (PdO) nanoparticles decorated titanium dioxide (TiO 2 ) thin film were studied. The TiO 2 thin films were prepared by the dc reactive magnetron sputtering. The Pd and PdO nanoparticles were sputtered on the top surface of TiO 2 surface in order to enhance the sensitivity to the H 2 gas. Morphologies, crystal structures, and chemical element of the examiner samples were investigated by the field-emission scanning electron microscopy (FE-SEM), grazing-incident X-ray diffraction (GIXRD), and X-ray photoelectron spectroscopy (XPS), respectively. The effects of the Pd and PdO nanoparticles on H 2 -sensing performance of TiO 2 were investigated over a low concentration range of 150-3,000 ppm H 2 at 50-250°C-operating temperatures. This result exhibited that the PdO decorated on TiO 2 surface showed very high response to H 2 at a low operating temperature of 150°C.