Hydrogen sensing characteristics of an Al-doped SnO2 thin film incorporated with palladium nanoparticles

An interesting hydrogen sensor prepared by an Al (3 at %)-doped SnO2 (ATO) thin layer decorated with palladium nanoparticles (Pd NPs) is demonstrated herein. The related hydrogen detecting characteristics are systematically investigated. The elemental and intrinsic properties are characterized by high-resolution scanning electron microscopy (HRSEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The specific surface area and catalytic ability are remarkably enhanced due to the presence of Pd NPs on the ATO thin layer. This causes the considerable improvement of hydrogen sensing behaviors. Under introduced 1000 ppm hydrogen gas in air, a higher sensing response of 3152 with a corresponding response and a recovery times of 17 s and 4 s and a lower detectable concentration of 50 ppb H2/ air are obtained at 225 degrees C for the studied Pd NP/ATO sensor. In addition, the studied sensor shows good repeatability and long-term stability. From a kinetic adsorption analysis, an activation energy about 43.6 kJ mol-1 is observed for this hydrogen detecting action. The studied Pd NP/ATO sensor also shows favours, e.g., simple device structure, easy production, lower consumed power, and a widespread sensing region of hydrogen gas content.