Study of a New Hydrogen Gas Sensor Synthesized With a Sputtered Cerium Oxide Thin Film and Evaporated Palladium Nanoparticles

A new hydrogen (H
₂
) gas sensor, synthesized with a radio frequency (RF) sputtered cerium oxide (CeO
₂
) thin film and rapid thermal evaporated palladium (Pd) nanoparticles (NPs), is fabricated and reported herein. The employed Pd NPs can effectively increase the surface area/volume ( S
_A
/V) ratio and catalytic reactivity of Pd metal, thereby substantially enhancing the adsorption effect of hydrogen molecules on the device surface and improving the related sensing performance. Energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to characterize the related properties of the studied device. Experimentally, a high sensing response of 120.2 under 1% H
₂
/air gas at 350 °C with a relatively shorter response (recovery) time of 5 s (17 s) is obtained. The studied Pd NP/CeO
₂
-based sensor device shows wide operating ranges of temperature (200 °C-400 °C) and hydrogen concentration (10 ppm-1% H
₂
/air). A thermodynamic analysis employed to study the surface coverage of hydrogen molecules is reported in this work. The studied sensor device also exhibits the advantages of a simple structure, easy fabrication process, and relatively low cost.