Enhancement of ethanol sensing of TeO2 nanorods by Ag functionalization

Gas sensors based on Ag–TeO2 composite nanorods were fabricated using thermal evaporation and sputtering techniques. The morphology, structure and phase composition of the as-prepared nanofibers were characterized by scanning electron microscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD), respectively. TEM and XRD showed that the nanorods and nanoparticles on them were tetragonal-structured single crystal TeO2 and a mainly amorphous phase, respectively. The multiple-networked bare TeO2 nanorod sensors exhibited a response of ∼219% at 25 ppm C2H5OH at 300 °C, whereas the Ag-functionalized TeO2 nanorod sensors showed a response of ∼808% under the same conditions. The mechanism by which the sensing properties of the TeO2 nanorods were enhanced by functionalization with Ag is also discussed.