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.