High-sensitivity hydrocarbon sensors based on tungsten oxide nanowires

Abstract

Hydrocarbon (LPG) sensors based on the nanostructures of V₂O₅ do not exhibit satisfactory characteristics, while sensors based on WO_2.72 nanowires show high sensitivity (∼1800) for 2000 ppm of LPG at 200 °C as well as relatively short recovery and response times. Impregnation of WO_2.72 nanowires with Pt in the 0.1–1.0 at% range, significantly improves the sensor characteristics, the sensitivity increasing with Pt concentration and reaching a value of ∼10⁶ for 2000 ppm of LPG in the 100–200 °C range with 1 at% Pt. The sensitivity remains high even for 50 ppm of LPG, and is not affected significantly by repeated cycles or humidity. The mechanism of sensing of hydrocarbons by WO_2.72 nanowires is explained on the basis of adsorbed oxygen species.