Preparation and structure dependence of H2sensing properties of palladium-coated tungsten oxide films

Meng Zhao, Jianxing Huang, Chung Wo Ong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

22 Citations (Scopus)


This study aims at revealing and explaining the influences of preparation condition on the structure and subsequent hydrogen (H2) sensing properties of palladium-(Pd-) coated tungsten oxide (WO3) films. The material structure was specified by grain size; porosity, surface roughness and thickness of the WO3layer; and thicknesses of the Pd coating. The structural parameters are found to be tailorable in broad ranges by applying supersonic cluster beam deposition or magnetron sputtering technique operating at various substrate temperatures (50-550°C) and 20% Ar-80% O2pressures (3-60 mTorr). The H2sensing response of the sensors, and their response time (trespond) for hydrogenation and recovery time (trecover) for dehydrogenation are detected and found to be adjustable in a comprehensive manner. Results indicate that Pd/WO3hydrogen sensors of high sensor response and short trespondand trecoverare achievable if the WO3-based sensor is made to be highly disordered or contain non-crystalline clusters of size ≤5 nm, and have a porosity ≥14%. More details on possible mechanisms responsible for the findings are discussed.
Original languageEnglish
Pages (from-to)1062-1070
Number of pages9
JournalSensors and Actuators, B: Chemical
Publication statusPublished - 15 Jan 2013


  • Grain size
  • H sensing 2
  • Palladium-coated tungsten oxide
  • Porosity
  • Roughness

ASJC Scopus subject areas

  • Instrumentation
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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