Rapid response hydrogen sensor based on nanoporous Pd thin films

Nanoporous structural palladium (Pd) thin films was achieved through DC sputtering technique and followed byannealed process under vacuum condition, which could origin from the melting of ultrathin Pd film on Si substrates and surface tension effect. The results exhibits that the porous structural Pd films would transformed into dispersive Pd particles with the increase of annealing temperature. Contacts of hydrogen sensor based on the Pd nanoporous thin films were then established using platinum (Pt) electrodes. The continuous Pd thin film and dispersive Pd particles show slow or even no hydrogen (H-2) sensing response, while the response is rapid for the Pd film with nanoporous structures. The Pd film annealed at 300 degrees C showed first-rank hydrogen sensing property (with response time of similar to 25 s and recovery time of similar to 10 s), which exhibited linear relationship response to H-2 with concentration from 0.04 to 1.2%. This sensing behavior would attributed to the electron scattering within nanoporous related to the dissociation of H-2 in Pd lattice. In addition, nanoporous Pd films also exhibited excellent selectivity against other reductive gases, such as CO, NH3, CH3OH etc. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.