Study of a Palladium Nanoparticle/Indium Oxide-Based Hydrogen Gas Sensor

An interesting hydrogen (H
₂
) gas sensor, synthesized by an indium oxide (In
₂
O
₃
) layer and evaporated palladium (Pd) nanoparticles (NPs), is manufactured and studied. The utilized Pd NPs essentially enhance the surface area/volume (
${S}_{A}/{V})$
ratio and catalytic reactivity of the Pd metal. Energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), high-resolution scanning electron microscopy (HRSEM), and TEM were used to investigate the relevant material behaviors of the proposed Pd NP/In
₂
O
₃
sensor device. The sensing mechanism is explicated in this study. A very high-sensing response of 5243 under 1% H
₂
/air gas with a response time of 12 s and an extremely low-detecting content of 100 ppb H
₂
/air were obtained at the optimal operating temperature of 225 °C. In addition, excellent selectivity toward hydrogen gas is observed for the studied device. The proposed sensor also shows advantages of simple structure, low-cost, and relatively easy fabrication process.