Enhanced performance of SnO2 nanowires ethanol sensor by functionalizing with La2O3

A SnO2 nanowires (NWs) sensor was coated with a functional La2O3 layer by solution deposition and its gas sensing characteristics were compared with those of an uncoated SnO2 NWs sensor. The responses (R-a/R-g, R-a: resistance in air, R-g: resistance in gas) of an undoped SnO2 NWs sensor to 100ppm C2H5OH and CH3COCH3 were 10.5 and 9.6, respectively, while those to 100 ppm C3H8, CO, and H-2 ranged from 3.1 to 3.3. The R-a/R-g values of the La2O3-coated SnO2 NWs to 100ppm C2H5OH and CH3COCH3 increased to 57.3 and 34.9, respectively, but there was no significant change in the responses to C3H8, CO, and H-2. The similar to 5.5-fold enhancement in R-a/R-g to C2H5OH as well as the selective detection of C2H5OH in the interference gases such as C3H8, CO, and H-2 was accomplished simultaneously by coating with La2O3. In particular, the selective discrimination Of C2H5OH over CH3COCH3, which is a difficult issue on account their similar chemical nature, was possible. (c) 2008 Elsevier B.V. All rights reserved.