Ni2O3 decoration of WO3 thin film for high sensitivity NH3 gas sensor

Abstract

A facile method for fabricating thin films of granular tungsten oxide (WO3) particles decorated with nickel oxide (Ni2O3) nanoparticles was developed for high response NH3 gas sensor. The WO3 granular film was fabricated by sputter deposition of tungsten, followed by oxidation. Ni2O3 nanoparticles were deposited onto the WO3 film by arc-discharge deposition of single-wall carbon nanotubes (SWCNTs) with Ni catalyst nanowires, followed by burning the carbon nanotubes. The Ni nanoparticle catalysts deposited on the SWCNTs were then oxidized to Ni2O3. The Ni2O3 nanoparticles on the surface exhibited a catalytic role in ammonia gas reactions. A maximum response of 13.5 at operating temperature of 250°C to 200 ppm NH3 gas concentration was found. In addition, the gas sensing mechanism of Ni2O3 decorated WO3 film was also discussed in this study.