Room-temperature optical detection of hydrogen gas using palladium nano-islands

(c) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Palladium thin films of different thicknesses have been processed by oxidation and subsequent reduction in hydrogen atmosphere. Hydrogen optical sensing properties of as deposited (Pd) and processed (r-Pd) samples have been experimentally tested with a H-2 concentration of 5% and 1%, discovering that the reduced films show improved performances in term of response/recovery time. As reveled by SEM images, the oxidation/ reduction process modifies the surface appearance, which assumes a nano-islands structured morphology. The porosity of the processed films may explain the reduction of the response/recovery time, while the larger effective sensing surface in thinner samples justifies the responsivity performances.