Enhanced CO gas sensing properties of Pt-functionalized WO3 nanorods

WO3 one-dimensional nanostructures were synthesized by using a simple catalyst-free thermal evaporation technique. Scanning electron microscopy observations revealed that the nanostructures were of a rod-like morphology with diameters in a range from a few tens to a few hundreds of nanometers and lengths up to a few tens of micrometers. The gas sensors fabricated from multiple networked WO3 nanorods functionalized with Pt showed enhanced electrical responses to both reducing gas CO and oxidizing gas NO2 at 300 °C. The sensitivity of the WO3 nanorods to CO gas has been increased twice by Pt functionalization. On the other hand, the sensitivities of WO3 nanorods to 10 and 100 ppm NO2 gas have been increased further, i.e., by 5.2 and 3.8 times, respectively. In addition, the mechanism for the improvement in the CO and NO2 gas sensing properties of WO3 nanorods by Pt functionalization is discussed.