Highly sensitive hydrogen sensors based on co-sputtered platinum-activated tungsten oxide films

Abstract Platinum-activated tungsten oxide (Pt–WO3) films for highly sensitive hydrogen (H2) sensors were co-deposited using radio frequency (r.f.) sputtering with subsequent two-step heat treatments. The Pt–WOx films were annealed at 700 °C for 1 h and then thermally treated at 450 °C for 24 h or 48 h. The microstructure, crystalline phase and composition of the as-sputtered, annealed and thermally treated films were characterized with scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The sensors were tested for 30–200 ppm H2 in air at different temperatures from 95 to 220 °C and with a relative humidity from 0 to 75%. The influences of Pt concentration and thermal treatment on the microstructure and the sensing performances of the Pt–WO3 films are presented in this work.

[1]  V. V. Malyshev,et al.  Investigation of gas-sensitivity of sensor structures to carbon monoxide in a wide range of temperature, concentration and humidity of gas medium , 2007 .

[2]  M. Schiavello,et al.  X-ray photoelectron spectroscopy study of nonstoichiometric tungsten oxides , 1977 .

[3]  C. Rivkin,et al.  An overview of hydrogen safety sensors and requirements , 2011 .

[4]  L. Boon-Brett,et al.  Reliability of commercially available hydrogen sensors for detection of hydrogen at critical concentrations: Part II – selected sensor test results , 2009 .

[5]  C. Bittencourt,et al.  Ag induced modifications on WO3 films studied by AFM, Raman and x-ray photoelectron spectroscopy , 2004 .

[6]  Hyeonsik Cheong,et al.  Pd-Pt alloy as a catalyst in gasochromic thin films for hydrogen sensors , 2009 .

[7]  W. Lour,et al.  Comprehensive investigation on planar type of Pd–GaN hydrogen sensors , 2009 .

[8]  Eduard Llobet,et al.  WO3 films modified with functionalised multi-wall carbon nanotubes: Morphological, compositional and gas response studies , 2006 .

[9]  Chao Zhang,et al.  Sensing properties of atmospheric plasma-sprayed WO3 coating for sub-ppm NO2 detection , 2010 .

[10]  C. Bittencourt,et al.  High-resolution photoelectron spectroscopy studies on WO3 films modified by Ag addition , 2005 .

[11]  Matteo Ferroni,et al.  Nanostructured WO3 deposited by modified thermal evaporation for gas-sensing applications , 2005 .

[12]  Wojtek Wlodarski,et al.  Hydrogen sensing characteristics of WO3 thin film conductometric sensors activated by Pt and Au catalysts , 2005 .

[13]  W. Wlodarski,et al.  Absorption spectral response of nanotextured WO3 thin films with Pt catalyst towards H2 , 2009 .

[14]  Chao Zhang,et al.  Deposition and microstructure characterization of atmospheric plasma-sprayed ZnO coatings for NO2 detection , 2010 .

[15]  Roghayeh Ghasempour,et al.  Pd doped WO3 films prepared by sol–gel process for hydrogen sensing , 2010 .

[16]  Sofian M. Kanan,et al.  Semiconducting Metal Oxide Based Sensors for Selective Gas Pollutant Detection , 2009, Sensors.

[17]  Chung-Chieh Chang,et al.  Hydrogen sensing characteristics of an electrodeposited WO3 thin film gasochromic sensor activated by Pt catalyst , 2007 .

[18]  Masanori Ando,et al.  Optical hydrogen sensitivity of noble metal–tungsten oxide composite films prepared by sputtering deposition , 2001 .

[19]  L. Lozzi,et al.  Core level and valence band investigation of WO3 thin films with synchrotron radiation , 2003 .

[20]  Norio Miura,et al.  Grain‐Size Effects in Tungsten Oxide‐Based Sensor for Nitrogen Oxides , 1994 .

[21]  Vladimir M. Aroutiounian,et al.  Metal oxide hydrogen, oxygen, and carbon monoxide sensors for hydrogen setups and cells , 2007 .