Characterization of hydrogen responsive nanoporous palladium films synthesized via a spontaneous galvanic displacement reaction

Nanotechnology. 2012 Nov 23;23(46):465403. doi: 10.1088/0957-4484/23/46/465403. Epub 2012 Oct 23.

Abstract

A model is presented regarding the mechanistic properties associated with the interaction of hydrogen with nanoporous palladium (np-Pd) films prepared using a spontaneous galvanic displacement reaction (SGDR), which involves PdCl(2) reduction by atomic Ag. Characterization of these films shows both chemical and morphological factors, which influence the performance characteristics of np-Pd microcantilever (MC) nanomechanical sensing devices. Raman spectroscopy, uniquely complemented with MC response profiles, is used to explore the chemical influence of palladium oxide (PdO). These combined techniques support a reaction mechanism that provides for rapid response to H(2) and recovery in the presence of O(2). Post-SGDR processing via reduction of PdCl(2)(s) in a H(2) environment results in a segregated nanoparticle three-dimensional matrix dispersed in a silver layer. The porous nature of the reduced material is shown by high resolution scanning electron microscopy. Extended grain boundaries, typical of these materials, result in a greater surface area conducive to fast sorption/desorption of hydrogen, encouraged by the presence of PdO. X-ray diffraction and inductively coupled plasma-optical emission spectroscopy are employed to study changes in morphology and chemistry occurring in these nanoporous films under different processing conditions. The unique nature of chemical/morphological effects, as demonstrated by the above characterization methods, provides evidence in support of observed nanomechanical response/recovery profiles offering insight for catalysis, H(2) storage and improved sensing applications.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Electrochemical Techniques
  • Hydrogen / analysis*
  • Hydrogen / chemistry
  • Nanostructures / chemistry*
  • Nanotechnology / instrumentation*
  • Nanotechnology / methods*
  • Oxygen / chemistry
  • Palladium / chemistry*
  • Silver / chemistry
  • Surface Properties

Substances

  • Silver
  • Palladium
  • Hydrogen
  • palladium oxide
  • palladium chloride
  • Oxygen