Fabrication, Structure, and Gas Sensing of Multiple-Networked Pt-Functionalized Bi₂O₃ Nanowires

Bi2O3 is highly sensitive to low concentrations of NO2 in ambient air and are almost insensitive to most other common gases. However, it still remains a challenge to enhance their sensing performance and detection limit. This study examined the influence of the functionalization of Bi2O3 nanorods with Pt on the NO2 gas sensing properties. Pt-functionalized β-Bi2O3 nanorods were fabricated by the thermal evaporation of Bi powder followed by sputter-deposition of Pt and annealing. The Pt-functionalized nanorods ranged from 100 to 300 nm in diameter and from a few tens to a few hundreds of micrometers in length. Multiple networked Pt-functionalized β-Bi2O3 nanorod sensors showed the responses of ~141 to ~313% at 1-5 ppm NO2 at 300 °C. These response values were 1.23-1.93 times higher than those of pristine Bi2O3 nanorod sensors at 1-5 ppm NO2. The origin of the enhancement of the sensing properties of the Bi2O3 nanorods by Pt functionalization is discussed.