title: Fast, sensitive hydrogen gas detection using single palladium nanowires that resist fracture.
abstract: Two types of pure palladium (Pd) nanowires, differentiated by microstructure, were electrodeposited: (1) nanocrystalline Pd nanowires (grain diameter approximately 5 nm, henceforth nc5-Pd) and (2) nanocrystalline Pd nanowires with a grain diameter of 15 nm (nc15-Pd). These nanowires were evaluated for the detection of hydrogen gas (H(2)). Despite their fundamental similarities, the behavior of these nanowires upon exposure to H(2) was dramatically and reproducibly different: nc5-Pd nanowires spontaneously fractured upon exposure to H(2) above 1-2%. Fractured nanowires continued to function as sensors for H(2) concentrations above 2%, actuated by the volume change associated with the alpha to beta phase transition of PdH(x). nc15-Pd nanowires, in contrast, withstood repeated exposures to H(2) up to 10% without fracturing. nc15-Pd nanowires showed a rapid (2 s at 10%) increase in resistance in the presence of H(2) and a response that scaled smoothly with [H(2)] spanning 5 orders of magnitude down to 2 ppm.
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: David K
authors.initials: DK
authors.lastname: Taggart
authors.forename: Reginald M
authors.initials: RM
authors.lastname: Penner
mesh_terms: D005740:Gases / Q000032:analysis*; D006859:Hydrogen / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D053770:Nanowires / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D005740:Gases; D010165:Palladium; D006859:Hydrogen